^Meteorology and Physical Oceanography^Avissar, Roni^Avissar, Roni^DE-FG02-92ER61453d the southern hemisphere extratropic213^1^Zeng,Fanrong^1994^6^A Large-Eddy Simulation Study of the Convective Boundary Layer in Complex Terrain: Implications for Subgrid-Scale Parameterizations in GCMs^M.S.^Rutgers University^31^Thesis^^^Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP)^^^^^^^389^^^^^^^^^^^^Meteorology and Physical Oceanography^Avissar, Roni^Avissar, Roni^DE-FG02-9S.^Rutgers University^39^Thesis^^^Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP)^^^^^^^387^^^^^^^^^^^matics, and Model Physics (CHAMMP)^^^^^^^383^^^^^^^^^^^^Meteorology and Physical Oceanography^Avissar, Roni^Avissar, Roni^DE-FG02-92ER61453rsity^61^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^4^^^^^^^^^^^^Agricultural Sciences^Biswas, P.K.^212^1^Li,Bin^1993^6^The Impact of the Spatial Variability of Land-Surface Characteristics on Land-Surface Energy Fluxes^M.rs Are of Greatest Importance for Atmospheric Models^M.S.^Rutgers University^78^Thesis^^^Computer Hardware, Advanced Mathe y^M.S.^Colorado State University^98^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^153^^^^^^^^^^^^Atmospheric Science^Stephens, Graeme L.^Stephens, Graeme L.^DE-FG03-94ER61748^rbon, Climate, and Vegetation^^^^^^^6^^^^^^^^^^^^Botany^Str 210^1^Collins,Dan C^1992^6^An Evaluation with the Fourier Amplitude Sensitivity Test (FAST) of Which Land-Surface Paramete 93^1^Schneider,Timothy L^1994^6^Backscattering by Nonspherical Ice Particles at Millimeter Wavelengths: A Theoretical Studs^Ph.D.^Colorado State University^202^Dissertation^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^151^^^^^^^^^^^^Atmospheric Science^Stephens, Graeme L.^Stephens, Graeme L.^DE-FC03-90ER61010^535^ation^^^Carbon, Climate, anA^152^The role of ice clouds in the hydrological cycle is uncertain. As a direct consequence, we do not fully understand t=92^1^Duda,David P^1994^6^Macrophysical and Microphysical Influences on Radiative Transfer in Two Dimensional Marine Stratu@mation (IPA) calculations of the same cross section. This matches the findings from Cahalan et al. (1994) for monochromati'c calculations in a simple cloud model, and suggests that accurate computations of domain averaged albedo in unbroken mari*ne stratus can be made using IPA calculations with one dimensional radiative transfer models.SєyZǑjK[AS6^1^Zhou,Chuan^1994^6^Spectral Correction of the Multi-Filter Rotating Shadowband Radiometer Shortwave Sensor^M.S.^State UVniversity of New York at Albany^58+^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^12^^^^^^^^^^^^Atmospheric Scien^ces^Michalsky, Joseph, and Lee Harrison^Michalsky, Joseph, and Lee Harrison^DE-FG02-90ER61072<Is`F&8aA^11^The multifilter rotating shadowband radiometer (MFRSR) measures total shortwave irradiance with an unfiltered silicono photodiode. The largest error terms in pyranometer measurements, in general, are caused by angular response and temperaturre response imperfections. In the MFRSR the temperature is held at a constant value, and the angular response deviation from ideal is measured before deployment and measurements are corrected accordingly. The main error in silicon photodiode radiometry arises because of the mismatch of spectral responses between the ideal wavelength-independent response sensor and the wavelength- dependent response of the silicon cell. To evaluate this error, total horizontal, diffuse horizontal, and direct normal irradiance measurements made with an absolute cavity radiometer-calibrated thermopile pyrheliometer and tra cking disk diffuse pyranometer are compared to the silicon response measurements made with an MFRSR. The root-mean-square !errors for the MFRSR without spectral corrections are significantly improved compared with standard silicon cell pyranomet"er with a 60% improvement in direct normal and a 55% improvement in diffuse horizontal irradiance. The spectral correction#s provide a relatively small additional improvement of 15 to 20% in the diffuse and total horizontal irradiances. Further,$ it is found that for five-minute measurements 40%, 30%, and 20% of the remaining difference in direct normal, total horiz%ontal, and diffuse horizontal irradiance measurements, respectively, arises from the difference in the time response of th&e silicon cell sensors (seconds) and thermopile sensors (seconds). Consequently, silicon cell pyranometry with root-mean-square errors of less that 10 W/m{+2} in each component are possible.뗌ڣŝ>wi?*EݩL]E%?}|y,(10^1^Benkovitz,Carmen M^1994^6^Development and Testing of a High-Resolution Model for Tropospheric Sulfate Driven by Obser)vation-Derived Meteorology^Ph.D.^New York University^265^Dissertation^^^Atmospheric Sciences^^^^^^^20^^^^^^^^^^^^Earth Sys/tem Science^Hoffert, Martin I.^Schwartz, Stephen E.^DE-AC02-76CH00016CH00016ion Measurement (ARM)n7 Aq|<2+A^19^A high-resolution three-dimensional Eulerian transport and transformation model has been developed to simulate concen,trations of tropospheric sulfate for specific times and locations; it was applied over the North Atlantic and adjacent con-tinental regions during October and November, 1986. The model represents emissions of anthropogenic SO{-2} and sulfate and. of biogenic sulfur species, horizontal and vertical transport, gas-phase oxidation of SO{-2} and dimethylsulfide, aqueous/-phase oxidation of SO{-2}, and wet and dry deposition of SO{-2}, sulfate, and methanesulfonic acid (MSA). The meteorologiS0cal driver is the 6-hour output from the forecast model of the European Centre for Medium-Range Weather Forecasts. CalculaU1ted sulfate concentrations and column burdens, examined in detail for October 15 and October 22 at 6Z, are related to exisX2ting weather patterns. These results exhibit rich temporal and spatial structure; the characteristic (1/e) temporal autocoi3rrelation time for the sulfate column burdens over the central North Atlantic averages 10 hours; 95% of the values were 25l4 hours or less. The characteristic distance of spatial autocorrelation over this region depends on direction and averages {51600 km; with 10th percentile value of 400 km and 90th percentile value of 1700 km. Daily average model sulfate concentrat~6ions at the lowest vertical level accurately represent the spatial variability, temporal episodicity, and absolute magnitu7des of surface concentrations measured by monitoring stations in Europe, Canada and Barbados; over 50% of model concentrat8ions are within a factor of 3 of the observations. Over 50% of weekly model sulfate wet deposition amounts are within a fa9ctor of 3 of observations from US monitoring stations. Over the 34-day period modeled, contributions from anthropogenic em:issions to the sulfate over the mid North Atlantic Ocean ranged from 44 to 66%, contributions from biogenic emissions were; between 6 and 12%. Calculated average yields for sulfate (47 to 72%) and MSA (13%), and turnover times for SO{-2} (2 to 3< days) and sulfate and MSA (4 to 8 days) are comparable to previous estimates; however, these quantities depend on meteorological conditions and on the geographic and vertical distributions.#c4jM 2[{5[D0U  @5S\8.^9KF$‰>9^1^Angevine,Wayne^1993^6^Heat and Momentum Flux Measurements in the Planetary Boundary Layer with a Wind Profiling Radar/?Radio Acoustic Sounding System^Ph.D.^University of Colorado^85^Dissertation^^^Atmospheric Radiation Measurement (ARM)^^^^^^^18^^^^^^^^^^^^Electrical and Computer Engineering^Avery, Susan^Gage, Ken^DE-AI06-91RL12090, DE-AI06-91RL12092RL12092W;AA^17^The planetary or atmospheric boundary layer is the lowest 100-2000 m of the atmosphere, and contains the sources of mBost energy and pollutants that affect the entire atmosphere. Boundary layer structure and dynamics are key to understandinCg, modeling, and predicting climate, weather and pollution. New and improved techniques for measuring the dynamics of the Dboundary layer are needed. Existing methods involving towers, surface measurements, or aircraft have limited flexibility oEr are expensive. This dissertation describes methods for measuring heat flux (virtual temperature flux) and momentum flux Fin convective boundary layers. The instrument used is the 915 MHz boundary layer radar wind profiler Radio Acoustic SoundiGng System (profiler/RASS). As the name suggests, the profiler was developed to make wind measurements, and this work is anH expansion of its capabilities. The radio acoustic sounding system uses the profiler and attachments to measure virtual teImperature. Before the profiler/RASS could be used to make flux measurements, the ability to make simultaneous measurementsJ of wind velocity and temperature had to be developed. A feasibility study was conducted in Platteville, CO in June 1991 tKo determine if flux measurements were a practical application of the profiler, with encouraging results. The Rural OxidantLs in the Southern Environment II (ROSE II) experiment in Alabama in June 1992 provided the opportunity to compare flux meaiMsurements from the profiler/RASS to those made by a surface sonic anemometer and an aircraft, The National Center for AtmokNspheric Research (NCAR) King Air. The results indicate that the profiler/RASS is capable of making heat flux measurements zOthat compare well with aircraft and surface measurements. The primary limitation on the precision of the measurements is t}Phe sampling uncertainty of the turbulence, a limitation that is the same for any fixed instrument. The feasibility of makiQng momentum flux measurements needs to be explored further in more favorable conditions. In the course of analyzing the flRux measurements, methods of determining the mixing depth (boundary layer height) and improved data quality control techniques were developed.IRTYN\kzLIfN\΋' k'jܓ#=Q6rUԜ2D6Q]m >zY8ԤmL 7LA@o"$ p13^1^Pulwarty,Roger S^1994^6^Annual and Interannual Variability of Convection over Tropical South America: 1980-1989^Ph.D.q^University of Colorado^220^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^26^^^^^^^^^^^^Geography^Barry, Roger G.^Bradley, Raymond S., and Henry F. Diaz^DE-FG02-ER69017^R69017^dᥖێ2V mBmLjNqX4L'3 &tsA^25^Analyses of temporal (and spatial) variability in a wide range of ocean and atmospheric indices suggest that the annutal cycle plays a central role in virtually all of the recognized principal modes of large-scale climatic variability (intruaseasonal variability, tropospheric quasi-biennial oscillation, El Nio-Southern Oscillation (ENSO) events). The major resvearch objective of this thesis is a study of the nature and controls of processes, associated with variability in convectiwon on these timescales, over the region of the South American 'monsoon'. Variability on multiple timescales are examined uxsing empirical orthogonal functions, lagged correlations and singular spectrum analysis. Unique aspects of the annual cyclye of convection over tropical South America are documented in detail. The study shows that the controls of convection and zcirculation differ from the Northern Hemisphere summer maximum, over Panama and the eastern tropical Pacific, to that in t{he Amazon Basin (Southern Hemisphere maximum). Changes in the onset, longevity, and trajectory of key convective centers, |associated with the annual cycle over different regions of tropical South America, appear to be modulated by sea surface t}emperature variations and gradients in the eastern Pacific and tropical Atlantic, location of the intertropical convergenc~e zone, phase of the-quasi-biennial oscillation etc. In particular, the southward and westward displacement of these centers, during strong ENSO 'warm' events, occur with widespread dryness over much of continental South America. Conversely, during strong 'cold' events, convection is restricted to locations north and eastward of the mean, resulting in higher rainfall over northern South America and Panama. The seasonal dependence of these influences, on climate and circulation over the region, is documented in detail. Interannual variability and trends are documented for rainfall over the central Amazon Basin, and for runoff in the Rio Negro/Amazon and Rio Parana/Paraguay river basins. Interactions and their evolution can lead to observed anomalies in circulation and seasonal precipitation, not always associated with ENSO, suggesting that 'wet' or 'dry' periods result from enhancement or suppression of the annual cycle. Further work is expected to include a study of the influence of ENSO events, with different development characteristics, on the seasonal cycle.hwzd+BC 2 }Q14^1^Hu,Yong-Xiang^1994^6^A Study of the Link Between Cloud Microphysics and Climate Change^Ph.D.^University of Alaska - Fairbanks^121^Dissertation^^^Quantitative Links^^^^^^^28^^^^^^^^^^^^Atmospheric Sciences, Geophysical Institute^Stamnes, KnNut^Stamnes, Knut^DE-FG06-90ER61020|u&J,ԁGjݤק%fbKZ}xXY`͘+62ǒ›EF[&ɚvA^27^The climate related cloud radiative properties (fluxes and heating rates) are found to be determined by the second and the third moments of the cloud droplet size distribution. The detailed distribution of the cloud droplet size is unnecessary to obtain for climate purposes. An accurate parameterization of cloud optical properties suitable for climate models is developed. A new radiative-convective model has been developed and used for studying cloud-climate interactions. The energy balance at the Earth-atmosphere interface is treated in a self-consistent manner which avoids artificial tuning. The cloud radiative properties are accurately incorporated and are suitable for sensitivity studies of cloud-radiation-climate interactions. A sensitivity study of role of the cloud microphysical properties in the climate system is performed by studying the impact of cloud radiative forcing on the equilibrium state temperature. The cloud equivalent radius is found to be a very important variable in the climate system. A climate sensitivity study is performed to highlight the important role of the cloud absorption. An adjoint radiative transfer method is developed for use in the cloudy and aerosol-loaded atmospheres. The physical meaning of the adjoint radiative properties are discussed. The method is expected to be useful in climate modeling and remote sensing studies. A preliminary study of the atmospheric irreversibility is performed to elucidate the connection between cloud microphysical properties and the macrophysical direction of global climate. A variational principle which describes the macrophysical character of the climate system is established.1v}qVȬZx¼L6he role of ice clouds in the atmospheric energy balance. It is therefore necessary to quantify the existence of ice clouds chemical analysis. S^1985^6^The Use of Climate Classification Schemes to Assess the Performance of General Circulation Mlla^70^Thesis^^^Quantitative Links^^^^^^^148^^^^^^^^^^^^Mechanical Engineering^Alofs, Darryl John^Williams, Allen^DE-FG02-A^139^Relative to aboveground responses of crops to elevated atmospheric CO{-2}, data on belowground responses are scarce. Furthermore, little data under field conditions have been collected. Therefore, field studies were undertaken for two yea"rs to investigate the effect of CO{-2} concentration (360 and 550 mol mol{+-1} and soil water regime [wet, 100% of evapotA^150^Recent estimates of the effects of increasing amounts of anthropogenic sulfate aerosol on global climate have indicated that its impact on the radiative forcing of the atmosphere may be comparable in magnitude to the effect from increases in CO{-2}. Much of this impact is expected from the indirect effects of the aerosol on global cloud microphysics and the =subsequent impact on cloud albedo. However, internal horizontal variations in cloud optical properties are also known to a@ffect cloud albedo and reflectance, and thus affect the remote sensing of cloud microphysics. A broadband solar radiative Stransfer model (SHSG) capable of simulating the radiances and fluxes in a medium that varies both vertically and horizontaVlly was used to quantify the effects of both cloud microphysical changes and cloud inhomogeneity changes on the radiative properties of marine stratus. Two dimensional cross sections of cloud physics data taken from a set of three dimensional RAMS/LES simulations of marine stratus provided realistic optical property data for radiative transfer simulations. Along with a control run using typical marine CCN concentrations, two studies using enhanced concentrations of CCN were examined. The results of the radiative transfer calculations indicated that in unbroken marine stratus clouds the _net_ horizontal transport of photons over a domain of a few km was nearly zero, and the domain average broadband albedo computed in a two dimensional cross section was nearly identical to the domain average calculated from a series of independent pixel approxiA^111^The phosphorus cycle is simulated to determine the relative roles of dissolved and particulate organic matter in the "organic carbon pump". Experiments in which all of the new production is balanced by an export of fast-sinking particles xproduce the following features: (1) higher-than-observed phosphate concentrations below regions of high surface upwelling (nutrient trapping), (2) new production in excess of primary production in the Southern Ocean, (3) regions where vertically-integrated new production is equal to zero, and (4) lower-than-observed phosphate concentration in the main thermocline. Nutrient trapping and low thermocline phosphate are especially severe when a particle-flux length scale consistent with sediment trap observations is used. When 80% of the new production is balanced by an export of DOM, and when this DOM has a lifetime which increases with depth, all of the above unrealistic features are either eliminated or become less prominent. This DOM model also reproduces fairly well meridional nitrate fluxes in the North Atlantic computed with inverse methods and the distribution of "new" DOC in the West Pacific, assuming a constant Redfield ratio of C:N:P = 105:16:1. It is suggested therefore, that DOM plays a major role in the downward transport of organic matter and that there is an as-yet undiscovered pool of DOP in the ocean. The oxygen cycle is simulated to determine the Redfield ratio of oxygen to phosphorus (_r_{-O2:P}). A model with _r_{-O2:P} = 138 predicts more realistically the distributions of AOU and denitrification than a model with _r_{-O2:P} = 172, suggesting that the classical value is closer to observed than the recent revision.with the A^136^The objective of this research is to build a sampling system to collect cloud condensation nuclei (CCN) in sufficient amounts for chemical analysis. The sampling system consists of three virtual impactors and two cloud chambers which are connected in series to collect a CCN sample within a critical supersaturation (S{-_c_}) range of 0.16% to 1.0%. The first cloud chamber, the haze chamber, subjects the air sample to 100% relative humidity in order to grow haze drops. The second virtual impactor then uses inertial separation to remove all particles with an S{-_c_} of less than 0.16%. The second impactor showed an S{-_c_} cutoff of approximately 0.16% although the sharpness of the cutoff was less than expected. The second cloud chamber, the continuous flow diffusion chamber (CFD), subjects the sample to a 1.0% supersaturation such as found in clouds, and removes only particulates with an S{-_c_} of less than 1.0%. The CFD showed an S{-_c_} cutoff of close to 1.5%. The slightly higher cutoff is likely due to temperature fluctuations within the CFD, but did not greatly affect the overall system performance. In general the sampling system gave an S{-_c_} collection range close to the expected although the overall efficiency was lower than expected, which results in a longer sampling time to collect sufficient sample for17^1^Oh,Jai-Ho^1989^6^Physically-based General Circulation Model Parameterization of Clouds and their Radiative Interaction^Ph.D.^Oregon State University^315^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^34^^^^^^^^^^^^Atmospheric Sciences^Schlesinger, Michael^Schlesinger, Michael^DE-AI02-93ER61589oundation grant ATM-8619459Pe7ոi-qdC*F<wA^33^A physically-based parameterization of clouds and their radiative interactions has been developed for a multilayer atmospheric general circulation model. The main purpose of this development is to enable the evaluation of cloud optical depth feedback, a feedback of potential importance for greenhouse-gas-induced climate change. In the cloud-radiation parameterization, cloud water is a prognostic variable; fractional cloud amount is predicted semi-prognostically; stratiform and cumuloform clouds can coexist in a vertical atmospheric column; clouds can exist either as liquid water, ice or mixed liquid water-ice clouds; the solar spectrum is subdivided into three bands, two for Rayleigh scattering and ozone absorption, and one for water vapor absorption which is further subdivided into six intervals for the k-distribution method; multiple scattering is calculated by the two-stream, delta-Eddington method; the longwave spectrum is divided into four regions based on the absorbers; the radiative properties of clouds depend on their predicted cloud liquid water and ice amounts; and the vertical distribution of clouds is considered to have maximum overlap for contiguous cloud layers and random overlap for noncontiguous cloud layers. The parameters for the stratiform-cloud parameterization and the values chosen are: (1) the characteristic time for the evaporation of cloud water, = 50 minutes; (2) the autoconversion rate of cloud water into precipitation, a = (3600 s){+-1}; (3) the threshold relative humidity of the environment at which condensation can begin, U{-00} = 0; and (4) the threshold cloud water above which precipitation can begin, m{-c,w} = 0.5x10{+-4} g/g for water clouds; m{-c,i} = 0.4xI{-c}(T{-c}) for ice clouds, where I{-c}(T{-c}) are the values given by Heymsfield and Platt (1984) as a function of the cloud temperature T{-c}; m{-c,i} = 1.2xI{-c}(T{-c}) for ice clouds formed from an antecedent cumuloform cloud. The parameters for the cumuloform-cloud parameterization and the values chosen are: (1) the characteristic time for the evaporation of cloud water, = 50 minutes; (2) the parameter in the diagnostic equation for the cloudiness in terms of the mass flux at the base of the detrainment layer, = 10; and (3) the conversion rate of cloud water into precipitation, C{-0} = 0.002 m{+-1}. In addition, two radiation parameters were determined: (1) the mass absorption coefficient of cumuloform ice clouds, a{-0}{+up-arrow,down-arrow} = 0.096; and the multiple-scattering asymmetry factor for cumuloform clouds, g = 0.85. An evaluation of the performance of the model shows that the cloud-radiation parameterization is capable of successfully simulating many features of the observed cloud cover, the vertically integrated cloud water, precipitation, and the earth's radiation budget at the top of the atmosphere. The model is less successful in reproducing the cloud optical depths as given by the International Satellite Could Climatology Project observations. This apparent contradiction suggests that these optical depth observations may not be useful in validating a cloud-radiation parameterization. The comparison of the simulated and observed climates also shows that the cloud parameterization is deficient in its reproduction of the subtropical stratocumulus clouds. To rectify this deficiency it is necessary to develop a model for stratocumulus clouds 18^1^Jiang,Xingjian^1991^6^Carbon Dioxide Induced Ocean Climatic Change and Tracer Experiment with an Atmosphere-Ocean General Circulation Model^Ph.D.^University of Illinois at Urbana-Champaign^304^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^36^^^^^^^^^^^^Atmospheric Sciences^Schlesinger, Michael^Schlesinger, Michael^DE-AI02-93ER61589oundation grants ATMA^35^The characteristic response time of the climate system ranges 10-100 years for a CO{-2} doubling due to the heat penetration into the deep ocean. This delay is of fundamental importance in establishing when the greenhouse signal will emerge from the background noise due to the natural variability of the climate system. It is imperative that we validate a model's estimate of the response time of the climate system against observations. If the penetration of the greenhouse-gas-induced heating into the ocean is analogous to that of a passive tracer, then the latter may be used as a surrogate for the former and thereby establish the characteristic response time. The principal objective of this study is to determine whether or not the penetration of a passive tracer is analogous to the penetration of a greenhouse-gas-induced heating. The Atmosphere-Ocean General Circulation Model (A-O GCM) developed at Oregon State University has been used to study CO{-2}-induced climate change and the penetration of passive tracers into the world ocean. The present climate and a 2xCO{-2} climate have been simulated. In this study, the passive tracers tritium, CFC-11, CFC-12 and a "passive CO{-2}-induced heating" are simulated. A rudimentary carbon-cycle model is also included for the purpose of a preliminary determination of the amount of atmospheric CO{-2} taken up by the ocean. The CO{-2}-induced active and passive warmings are larger in the subtropics and high latitudes than in the tropics. The largest difference between the active and passive CO{-2}-induced heatings occur in the North Atlantic deep ocean, with maximum cooling about -1.5 C for the active case in layer four of the ocean (1150 m). There is no hemispherically asymmetric warming as that found by Manabe et al. (1990) and Stouffer et al. (1990). The convective overturning and large-scale sinking motion are responsible for the large penetration of CO{-2}-induced warming in high latitudes. The CO{-2}-induced circulation changes show that the North Atlantic thermohaline circulation is signifi cantly weakened due to the penetration of CO{-2}-induced heating. Associated with this change, the strength of North Atlantic conveyor belt is reduced, which results in a large warming in the upper ocean and cooling in the deep layers. The characteristic response time ranges from 40-50 years for the active CO{-2}-induced climate change, and 70-160 years for passive CO{-2}-induced climate change. The physical processes controlling the geochemical tracer penetration are very similar to those for the CO{-2}-induced heating. Detailed comparisons between the penetrations of the CO{-2}-induced heating and passive tracers show that there is no a single tracer, whether tritium, CFC-11, CFC-12 or the passive CO{-2}-induced heating, which penetrates into the ocean exactly like the active CO{-2}-induced heating in terms of distribution, transport or physical process. The overall results indicate that CFCs may be the best candidate as a surrogate for the CO{-2}-induced oceanic climate study. The carbon-cycle study shows that the model is capable of simulating the observed ocean-atmosphere pCO{-2} difference (delta-pCO{-2}) in most areas. However, the model cannot simulate the observed magnitude and detailed geographical distribution of delta-pCO{-2} because they are also determined by the organic and biological processes which are neglected in the present study. The model-simulated ocean uptake of atmospheric CO{-2} is about 2.61 GtC per year, which is" about 38.65.6% of the anthropogenic atmospheric CO{-2} released during the last decade.,.6t<;t u%19^1^Entwistle,Clarence Bruce^1992^6^Analysis of the Nature of Zero Feedback in the Climate System Using a Multilayer Radi2ative-Convective Model^M.S.^University of Illinois at Urbana-Champaign^201^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^538^^^^^^^^^^^^Atmospheric Sciences^Schlesinger, Michael^Schlesinger, Michael^DE-AI02-93ER61589oundation grant ATM-9001310OA^37^The radiative-transfer-model (RT) feedback analysis method [Manabe and Wetherald (1980), Wetherald and Manabe (1980, S1988)] described by Schlesinger (1989) can provide an economical means of ranking the feedback processes in general circulh ation models (GCMs). To test the accuracy of this method a radiative-convective model (RCM), which can provide a true meask ure of feedback, is used. However, results of the RT method using a two-layer RCM developed from the radiative transfer pa rameterization of the Oregon State University two-layer GCM raise fundamental questions concerning the definition and natu re of zero feedback. To answer these questions a multi-layer RCM was developed based upon the radiative transfer parameter ization of the University of Illinois multi-layer GCM (Oh, 1989). Introduction of forward time marching to the multi-layer radiative transfer code revealed the need for modification. Accordingly, the radiative transfer code was modified and evaluated in comparison with 37 other such models that participated in the Intercomparison of Radiation Codes in Climate Models (ICRCCM) study. To answer the fundamental questions on the nature of zero feedback in the climate system, the MLRCM was run for two perturbation experiments, a one percent increase in the solar constant and a doubling of the CO{-2} concentration. Results from these experiments show that the non-vertically resolving, zero-dimensional planetary energy balance model prediction of the zero-feedback surface temperature change due to a change in external forcing gives the correct answer for a vertically resolving, one-dimensional model, provided that the change in planetary emissivity as the climate systemP responds to that forcing is included. Also, it is concluded that the zero-feedback climate system includes the processes of radiative transfer, surface convection and temperature-independent convective adjustment in the free atmosphere. TemperQature-dependent convective adjustment is not included, as it creates a feedback. Additionally, it is found that the vertical profile of the zero-feedback temperature change is not uniform with height, and depends upon the perturbation applied tRo the climate system.mH%^s5u:՞h/ |ԟ #WLn;hFlFpޯI  wVq3WCs6[#⏞.!|x20^1^Ramankutty,Navin^1994^6^An Empirical Estimate of Climate Sensitivity^M.S.^University of Illinois at Urbana-Champaign^I167^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^40^^^^^^^^^^^^Atmospheric Sciences^Schlesinger, Michael^Schlesinger, Mi-chael^DE-AI02-93ER61589oundation grant ATM-9001310xgvCQ{ JUeTh떧SXup6kd(xے@7Wȵh⢟JA^39^The Intergovernmental Panel on Climate Change (IPCC) estimates the climate sensitivity to be in the range 1.5 to 4.5KC, with a best guess of 2.5C (Houghton et al., 1990, 1992), while Lindzen estimates delta-T{-2x} = 0.5C (Lindzen, 1990).K The IPCC estimate is based on equilibrium simulations using General Circulation Models (GCMs). This study presents an alt ernate method of estimating delta-T{-2x} using an empirical approach combining simple climate/ocean model simulations witho! observations. The same procedure is applied to narrow the range of uncertainty in the estimate of radiative forcing due tr"o some climate forcing agents. Our study yields an estimate of delta-T{-2x} = 2.9{-+2.3}{+-1.2}C, corresponding to estima#ted anthropogenic sulphate aerosol (ASA) forcing of delta-F{-SO4}(1978) = -0.6{--0.3}{++0.5} Wm{+-2}. This range of sensit$ivity is 17% larger than the IPCC range, but our estimated range of ASA radiative forcing is much smaller than the estimat%es from direct radiative-transfer calculations of -0.90.6 Wm{+-2}. Putative long-term solar-irradiance variations imply a& range of delta-T{-2x} = 1.6{-+3.6}{+-0.6}C, corresponding to a range of delta-F{-SO4}(1978) = -0.5{--0.6}{++0.4} Wm{+-2}'. A case is made for the plausibility of long-term solar-irradiance variations, but direct observational or physical evide(nce is still wanting. We use our simple model to detrend the observed temperature record and identify an oscillation of 65)-70-year timescale. The oscillation is confined to the North Atlantic and bounding Northern Hemisphere continental regions*. We believe that it is caused by internal ocean dynamics rather than external forcing. We have explored the implications +of volcanic aerosol forcing on global-mean surface temperatures. We estimate the cooling due to volcanic aerosols to be -1,.6{--1.5}{++0.8}C per unit aerosol optical depth. We also find evidence for cumulative long-term cooling due to frequent -occurrence of eruptions. However, this long-term cooling does not explain the warming-cooling-warming phases of the observ.ed temperatures from 1910-1970, as has been conjectured by Lamb (1970), Robock (1978, 1979) and Bryson and Goodman (1980). We find that climate sensitivity has a significant influence on the temperature response to volcanic forcing, contradicto021^1^Ackerman,Andrew S^1994^6^A Numerical Modeling Study of the Effects of Variations in Aerosol Concentrations on Stratif1orm Clouds in the Marine Boundary Layer^Ph.D.^University of Washington^230^Dissertation^^^Atmospheric Radiation Measurement (ARM)^^^^^^^42^^^^^^^^^^^^Atmospheric Sciences^Hobbs, Peter V.^Toon, Owen B., and Douglas L. Westphal^DE-AI03-94ER617433A^41^Marine stratiform clouds play an important role in the global radiative heat budget of the Earth because they overlie4 about a third of the oceans and they reflect much more sunlight than the ocean surface. The reflectivity of these clouds 5depends in part on the concentrations of cloud condensation nuclei (CCN) on which cloud droplets form. Here a numerical mo6del is used to investigate interactions between aerosol and cloud microphysics, radiative transfer, and turbulent mixing i7n the stratiform cloud-topped marine boundary layer. Results from model simulations are found to be in general agreement w8ith airborne measurements of marine stratocumulus clouds. However, the model underpredicts the concentrations of small clo+9ud droplets in the lower region of the cloud layer. This is consistent with the lack of a peak supersaturation near cloud -:base in the model results, which is attributable to horizontal averaging in the model. The model simulations indicate that; equilibrium CCN concentrations are sensitive to their formation rate. The times required to reach equilibrium were found tions than under the assumptions that cloud water is fixed and unactivated haze particles are ignored. Increased droplet cs?oncentrations generally (but not always) produce increased cloud water due to reduced drizzle. The number of haze particlev@s increases with droplet concentrations due to decreased peak supersaturations in the cloud. The model simulations show thAat when droplet collisions reduce droplet concentrations to extremely low values, a cloud layer can become so optically thBin that cloud-top radiative cooling is unable to drive vertical mixing. The stratocumulus-topped marine boundary layer canC then collapse to a shallow fog layer over the course of a day or more. The model was also used to investigate long-lived,D linear regions of enhanced cloud reflectivity that appear in satellite imagery downwind of ships. We have found that injeEctions of CCN, which are present in ship exhaust, can account for many of the observed properties of ship tracks. Ship traFcks are classified as Type 1, which are observed in visible satellite imagery, and Type 2, which are more common and are o~Gbserved in near-infrared imagery. The distinction between the two types is attributed to differences in ambient concentratHions of CCN that cause variations in turbulent mixing in the marine boundary layer, through the effect of cloud droplet concentrations on cloud-top longwave radiative cooling. C29c1U$C%`hԆRh<$!L !CN2`uDЃ`eq&d159^1^Li,Long^1994^6^The Global Atmospheric Response to Low Frequency Tropical Forcing^Ph.D.^University of California at D160^1^Ross,John Alan^1993^6^An Algebraic Stress Finite Element Model for Recirculating Turbulent Flows^Ph.D.^University of161^1^Nevison,Cynthia Dale^1994^6^A Model Analysis of the Spatial Distribution and Temporal Trends of N{-2}O Sources and Sgreater than 1.0 ppbv with maximum values of 1.7 ppbv. The PAN to O{-3} ratio relationship appears to be dependent on the ent, depending on the turnover time of the soil organic material. Using radiocarbon measurements and a simple model, I hav81^1^Medley,Steven D^1993^6^Collection of Cloud Condensation Nuclei for Chemical Analysis^M.S.^University of Missouri - Ro#es^^^^^^^307^^^^^^^^^^^^Chemistry^Zoller, William H.^Gaffney, Jeffrey S., and Nancy A. Marley^W-31-109-ENG-38, W-7405-ENG-'156^1^Ghan,Steven John^1988^6^Unstable Radiative-Dynamical Interactions^D.Sci.^Massachusetts Institute of Technology^180^T7157^1^Kinnison,Douglas Edward^1989^6^Effects of Trace Gases on Global Atmospheric Chemical and Physical Processes^Ph.D.^Un;158^1^Atherton,Cynthia Shaver^1994^6^Predicting Tropospheric Ozone and Hydroxyl Radical in a Global, Three-Dimensional, ChIT26^1^Daniels,RC^1991^6^An Internship with the Carbon Dioxide Information Analysis and Research Program at Oak Ridge NationLal Laboratory: The Effects of Greenhouse Gas Induced Sea Level Rise on the South Carolina Coast^M.A.^Miami University^174^^V27^1^Jastrow,Julie D^1994^6^Mechanisms of Aggregate Formation and Stabilization in Prairie Soils^Ph.D.^University of IllinaWois at Chicago^115^Dissertation^^^Ecosystems Function and Response^^^^^^^49^^^^^^^^^^^^Biological Sciences^Lussenhop, Johnl^Miller, R. Michael^W-31-109-ENG-38^7rJFUBfG9A %'pHܛaX0{A^=~ ?0'zZ/T/c:lFqTd X!pYA^48^Water-stable soil aggregates were studied in mollisols recovering from long-term cultivation. The general hypothesis Zinvestigated was that plant roots and fungal hyphae provide a mechanical framework for the formation of soil aggregates an[d, thereby, create the conditions necessary for the accrual of organic matter, which serves to further stabilize the aggre\gates. This hypothesis was investigated in three ways. First, the contributions of roots and the external hyphae of mycorr]hizal fungi to the formation and stabilization of macroaggregates (>0.25 mm in diameter) in restored tallgrass prairie wer^e shown to be greater than the effects of microbial biomass, water-soluble carbon, and total soil organic carbon by using _the statistical technique of path analysis. It was also demonstrated that the relative importance of different organic bin`ding mechanisms was generally a function of the physical size of the mechanism relative to the spatial scale of the aggregaate planes of weakness being bridged. Second, in a chronosequence of prairie restorations, the accrual of soil organic matbter was facilitated by, but lagged behind, the formation of macroaggregates. Inputs of particulate organic matter appearedc to be incorporated relatively rapidly into a mineral-associated fraction, which may be an important factor in aggregate sdtabilization. Third, carbon inputs and turnover rates in micro- and macroaggregates were compared by using the natural abuendance of stable carbon isotopes, which clearly demonstrated a much slower turnover of old carbon in microaggregates. Measfured increases in the net inputs of new carbon with increasing aggregate size confirmed the existence of an aggregate hiergarchy created by the binding of microaggregates into increasingly larger macroaggregates. Unexpectedly, the stable isotopeh data indicated that microaggregate formation and degradation may be more rapid than suggested by the apparent stability of microaggregates in cultivated soils or by the turnover rates for old carbon.*;DFՙxaXd &ꏻ?qbgp'pj28^1^Franson,Raymond L^1989^6^Mechanisms of Belowground Interactions among _Plantago lanceolata_, _Phleum pratense_ and _G klomus monosporum_^Ph.D.^University of Chicago^108^Dissertation^^^Ecosystems Function and Response^^^^^^^51^^^^^^^^^^^^Comm ittee on Evolutionary Biology^Miller, R. Michael^Miller, R. Michael^W-31-109-ENG-38^Px!J4Fv:}VIx> mA^50^A study of belowground interactions between two oldfield herbs was conducted to determine which of the many possible nmechanisms of interactions between plants occur and what is the relative importance and interrelationship of those that do 'o occur? Although mechanisms of plant interactions cannot be directly observed, the mechanisms by which plants are allowed pto interact can be manipulated and then the net result can be quantified. The experimental design is a complete factorial qcomposed of two plant species (_Plantago lanceolata_, _Phleum pratense_), two levels of fungal inoculation (addition of _Grlomus monosporum_, without addition of _G. monosporum_), four levels of belowground barrier between plants (no barrier, 20 *s micron mesh, 1 micron mesh, solid barrier), and three potential partners (_Plantago_, _Phleum_, no neighbor), and four re -tplicates. We found _Glomus_ partially alleviates the depressive effects of increasing density in _Plantago_ in monoculture ?u. _Phleum_ shows no response to _Glomus_ colonization. Without _Glomus_, _Plantago_ achieves a larger gain in biomass whil Cve _Phleum_ is suppressed only minimally. When _Glomus_ is added the net result of _Plantago-Phleum_ interactions changes f [wrom competitive to commensal. _Plantago_ achieves a higher growth rate while growing with _Phleum_ than it can when grown ^xalone while _Phleum_ achieves nearly the same biomass whether growing alone, in monoculture or with _Plantago_. This sugge mysts that _Phleum_ acts as a "root promoter" causing an increase in root mass, root length and specific root length of any qzplant growing with it. The use of meshes allows determination that all mechanisms of interaction in the experiment involved chemicals or microbes of less than 1 micron in diameter.RØC2s6]go69vNL6PQB`)T3ܕGX0O|29^1^Reinhardt,Debra R^1989^6^Growing Season Dynamics of Vesicular Arbuscular Mycorrhizal Fungi in Prairie Versus Pasture }Ecosystems^M.S.^University of Illinois at Chicago^42^Thesis^^^Ecosystems Function and Response^^^^^^^53^^^^^^^^^^^^Biologi cal Sciences^Lussenhop, John^Miller, R. Michael^W-31-109-ENG-38^5rz#@[]LmPsʯ:O;Pd2{Kÿ4 A^52^This study addresses the hypothesis that there is a community effect for levels of intraradical and extraradical vesi cular-arbuscular mycorrhizal fungal colonization of fibrous roots, based on general root morphology and phenology. Two gra ssland communities, a reconstructed prairie characterized by a predominance of warm-season grasses and an ungrazed pasture  composed of cool-season grasses, were chosen as the study sites because of their differences in root morphology as well as phenology. A community effect for the biomass of roots larger than 1.0 mm in diameter was found to occur. A significantl y greater amount of root biomass was in this size class in the prairie as compared to the pasture. However, the biomass of fibrous roots, i.e., roots less than 1.0 mm diameter, did not differ significantly between the two communities. Fibrous r oot length was significantly greater in the pasture than in the prairie due to greater lengths of medium (0.075-0.2 mm diapmeter) and fine (< 0.075 mm diameter) fibrous roots. Although a greater total length of total length of fibrous roots occu rred in the pasture community, the amount of VAM fungus as represented by total length of roots colonized was similar for the prairie and pasture communities (P = 0.34). However, the colonized lengths within the various size classes of fibrous roots differed between the two communities. Therefore, a pattern of fungal colonization which would explain the intraradical distribution among root size classes based on "susceptibility" of each size class to colonization was sought. A measure  of "susceptibility to colonization" by VAM fungi for each size class of root was determined by dividing the proportion of  total root length within a diameter size class by the proportion of total root length within that size class. These values demonstrated that the finer the fibrous root size class, the less susceptible it was to colonization. The susceptibility values for two of the three size classes were not significantly different for the two communities, indicating that the im portance of root diameter in determining level of colonization is similar in the two communities.|.ß[C p_Z'҄'Lѐd+B (:x!OwKn81KD,pWXpͬf$w}$T-1 sh1|30^1^Smith,William Scott^1994^6^A Study of the Cloud/Radiation Interaction Using a Second Order Turbulence Closure Radiative/Convective Model^Ph.D.^New Mexico State University at Las Cruces^283^Dissertation^^^Atmospheric Radiation Measurement ( ARM)^^^^^^^56^^^^^^^^^^^^Physics^Chen, T.-W., and C.-Y. J. Kao^Kao, C.-Y. Jim^W-7405-ENG-36^5-ENG-36^d$IZ+M$?8P A^55^A high resolution one-dimensional version of a second-order turbulence radiative/convective model, developed at Los A lamos National Laboratory, is used to simulate the diurnal cycle of marine stratocumulus clouds with respect to their inte raction with radiation and turbulent mixing. Particular attention is given to the role of shortwave heating in modulating the diurnal variation of the stratocumulus-capped boundary layer. The fidelity of the model to the underlying physics is a ssessed by comparing the model simulation against data taken at San Nicolas Island during the intensive field observation (IFO) of the First International Satellite Cloud Climatology Program (ISCCP) Regional Experiment (FIRE), conducted during June and July, 1987. The model is able to reproduce the observed diurnal cycle of the liquid water content, cloud base hei ght, radiative heating or cooling rates, and the mean and turbulence variables fairly well. The mechanisms which cause the diurnal variation and the decoupling of the boundary layer are examined.#dZiCנnmw_[)32>80q2 31^1^Crouzet,Yoan^1993^6^Equilibrium Vapor Pressure and Capillary Ring Formation of Adhering Spherical Aerosol Particles^M .S.^Texas A&M University^130^Thesis^^^Atmospheric Sciences^^^^^^^58^^^^^^^^^^^^Nuclear Engineering^Marlow, William H.^Marl ow, William H.^DE-FG02-91ER61207^*vB on0M[|WڬfJF~ `tZ ָEQ-牘8H FGt A^57^Liquid rings trapped by capillary condensation at the point of contact between two spherical particles present an int -eresting feature insofar as they often display negative curvatures, thereby inducing a lowering of the equilibrium vapor p 0ressures according to the Kelvin equation. This thesis work is divided up into two parts, and each part corresponds to a specific approach of the problem and different objectives. The first part of this work dealt with the calculations of the mean curvature of the meniscus for any two spherical particles in contact. Results were interpreted in terms of equilibrium vapor pressure and applied to condensation nuclei activation. Critical supersaturations were defined and compared to the predictions of the heterogeneous nucleation model for the case of water. A few applications were listed. The second part o Of this thesis work attempted a different approach by taking into consideration the van der Waals interaction forces acting R at a molecular level. The liquid was modeled as an assembly of one-nanometer liquid spheres, and a Monte Carlo code was d oeveloped in order to find the minimal energy configuration of the system. Energies were computed using Lifshitz theory bet rween macroscopic spheres. A simulation was performed for a specific case: liquid water and two hexadecane solid particles ~in contact. The final configuration of the assembly was first analyzed in order to estimate the contact angle; the interfa ce was then compared to the predictions of the previous approach. A very encouraging agreement was found on a qualitative level.AP鋪>УhA ^DюT2!$1vl%vlα&{wg; LIl笽>>CV=&k=|i3Siqa185^1^Kwon,Tae-Yong^1993^6^An Examination of the Time/Space Averaging Process Used in the Earth Radiation Budget Experiment^Ph.D.^State University of New York at Stony Brook^99^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^334^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Cess, Robert D.^Cess, Robert D.^DE-FG02-85ER60314K~طJF/\ l- 33^1^Steig,Eric Julien^1992^6^A Gas Extraction System for the Measurement of Carbon Dioxide and Carbon Isotopes in Polar I ce Cores^M.S.^University of Washington^52^Thesis^^^Graduate Fellowships for Global Change^^^^^^^61^^^^^^^^^^^^Geological S ciences^Stuiver, Minze^Wohlpart, A.^DE-AC05-76OR00033^76OR00033^\D굄S#L첬A.*Rʼjkou .4N+`F. A^60^Knowledge of the distribution of {+13}C in the glacial ocean, atmosphere, and biosphere is important to understandin g the causes of glacial/interglacial changes in atmospheric CO{-2} levels. Although, deep-ocean {+13}C values are well-co nstrained by ocean sediment studies, model-based estimates of changes in the carbon budget for the biosphere vary considerably. Measurement of atmospheric {+13}C in CO{-2} in ice cores will provide additional constraints on this budget and will also improve estimates of changes in the ocean surface layer {+13}C. Direct measurement of ancient atmospheric {+13}C can be accomplished through polar ice cores studies. I have designed and constructed a gas-extraction line for ice cores w ith particular attention to the specific difficulties of measuring {+13}C in CO{-2}. The ice is shaved, rather than crush ed, to minimize fractionation effects resulting from gas travel through long air-paths in the ice. To minimize the risk of  isotopic contamination and fractionation within the vacuum line, CO{-2} is separated immediately from the air; the CO{-2}  concentration is then measured by a simple pressure/volume comparison rather than by gas chromatography or spectroscopy. Measurements from Greenland ice core samples give an average value of 2802 ppm CO{-2} for pre-industrial samples, demonst -rating that the extraction system gives accurate, precise determinations of CO{-2} concentrations. Measurement of {+13}C 0from polar ice samples has not been achieved at this time. However, results on standard air samples demonstrate a precisio 9n for {+13}C of less than 0.2% at the 95% confidence level.w_03r/эJ_>)d7)8{ם@h%_yH =34^1^Shen,Karin Pauline^1992^6^A Microclimate Model to Investigate Greenhouse Warming of a Sub-Alpine Ecosystem^M.S.^Unive Hrsity of California at Berkeley^64^Thesis^^^Graduate Fellowships for Global Change^^^^^^^63^^^^^^^^^^^^Energy and Resource Ks Group^Harte, John^Wohlpart, A.^DE-AC05-76OR00033 > ?k'R ܈ LS<L_y;:S£B_6pρ,+t>A^62^Increasing concentrations of greenhouse gases in the earth's atmosphere are expected to result in a global warming of U several degrees Celsius in the coming decades. This warming will have far-reaching impacts on the biosphere, and while Ge gneral Circulation Models (GCMs) try to predict the magnitude and scope of the warming, there is little information regardi ing the potential impacts of greenhouse warming on natural systems. An experiment currently under way in a meadow in the Co vlorado Rocky Mountains attempts to investigate the many consequences of greenhouse warming for soil ecosystems. A mathemat xical model of the soil microclimate was developed to simulate the soil temperature and moisture content of the meadow. The model simulates both treatment and control scenarios so as to investigate the potential effects of warming. Results of mo del simulation studies indicate warmer, drier soils under treatment conditions showing the greatest temperature effects of warming occurring at night. These results could have several implications regarding the dynamics of the ecosystem, and future model studies will investigate these connections.qls3\ ˕_1+(/];3XQtSۄ{Hm/Df[E 35^1^Dean,Caryn Lyn^1993^6^Interactions Between a Tropical Mixed Boundary Layer and Cumulus Convection in a Radiative-Conv ective Model^M.S.^Pennsylvania State University^159^Thesis^^^Graduate Fellowships for Global Change^^^^^^^65^^^^^^^^^^^^Me teorology^Frank, William^Wohlpart, A.^DE-AC05-76OR00033033ש:¤h)I (X*,` Ԫ'-~`gd4IS"c A^64^A radiative-convective model, combining previously developed cumulus, stable cloud and radiation parameterizations wi th a boundary layer scheme, was developed in the current study. The cloud model (Frank and Cohen, 1985) was modified to in corporate the effects of both small and large clouds. The boundary layer model, adapted from a mixed layer model (Albrecht  et al. 1979), was only slightly modified to couple it with the more sophisticated cloud model. The model was tested for a  variety of imposed divergence profiles, which simulate the regions of the tropical ocean from approximately the Intertropical Convergence Zone (ITCZ) to the subtropical high region. The sounding used to initialize the model for most of the runs is from the trade wind region of ATEX. For each experiment, the model was run with a timestep of 300 seconds for a perio d of seven (7) days. The model produced an inversion height of approximately 950 mb for each region. As the subsidence inc reased, typical of conditions towards the subtropical high region, the boundary layer became moister and warmer, and the p !eriods of deep convection became weaker and less frequent. Various cloud spectra were also introduced into the model to te %st for sensitivity to the number of cloud types represented. The model produced similar results whether one cloud or many 1clouds were used. However, the runs with more than one cloud generally displayed resultant inversion heights with more sta 4ble oscillations than the equivalent runs with only one cloud type. With the exception of higher mixing rates resulting in 9 larger clouds, the specification of initial updraft vertical velocity and mixing rate made little difference to the final < inversion height and boundary layer thermodynamic values. Finally, sensitivity tests were done for varying sea surface te Lmperatures and surface wind velocities. The model responded well to changes. As sea surface temperature increased, the inv Oersion height increased, the boundary layer became warmer and the moisture stayed approximately the same. As surface wind hvelocity increased, the inversion height decreased, and the boundary layer temperature and moisture decreased and increase ld, respectively. A FGGE sounding from a region closer to the equator was tested and the results were very similar, with an  inversion height near 960 mb. Therefore, the model is thought to be physically representative of the physical area descri bed above.L\ft阨rrjELF&eqdNR.K9>u3ӥJ4Kޝb0$`@To!@J dE2<+agI|%A/JƐ! 36^1^Jensen,Deborah Bowne^1993^6^Population Differentiation in Tree-Ring Growth Responses of White Fir (_Abies concolor_) to Climate: Implications for Predicting Forest Responses to Climate Change^Ph.D.^University of California at Berkeley^143^ Dissertation^^^Graduate Fellowships for Global Change^^^^^^^67^^^^^^^^^^^^Energy and Resources Group^Harte, John^Wohlpart, in addition to their hitherto accepted use for studying equilibrium properties of climate.Ig%,G?Bⓔ\%QjS RiKU~k#Svq1cS÷~ᄟ~ ㄍGԤ3"VJS -62`IKQfx+R*hѵNNk_"YnƊ^9(B !4vfsW$QМkGO=NGÔfvt86j jS6K2@WJT˕3}.)2bư238*:ic Ru VW 0.817 and 0.672 mol m{+-2} s{+-1}, respectively; for sorghum, these values were 0.515 and 0.339 mol m{+-2} s{+-1}, resp*?ectively. Sunflower grown with the high night temperature had a higher concentration of carbohydrates than sunflower grown-@ under the ambient night temperature. Carbohydrate concentration in sorghum grown with high night temperature was not consHAistently higher or lower than that in sorghum grown with ambient night temperature. Height of both sunflower and sorghum wKBas reduced by elevated night temperature. After 74 days of exposure to the two different temperatures, sunflower grown und\Cer the ambient night temperature was about 30 cm taller than the sunflower grown under elevated night temperature; for sor_Dghum, the difference was about 25 cm. For sunflower, flowers of plants grown under the elevated night temperature appearedlE one week earlier than flowers of plants grown under the ambient temperature. For sorghum, no flowers formed under either oFtreatment by harvest (74 days after planting). The results suggest that, if night temperatures do increase due to climate {change, development of flowers of sunflower will be hastened.of winter to summer concentration were observed to be unifor~nges between the equatorial region and shallow layers of the temperate thermocline. Parallel model runs for {+90}Sr and tr pslands introduced almost half of the present-day {+90}Sr inventory into the Pacific Ocean. An upper ocean Pacific model wiIGCarbon, Climate, and Vegetationpart, A.^DE-AC05-76OR00033odel and a box model constrain OH at northern midlatitudes to JGAtmospheric Radiation Measurement (ARM)ions of 1) non-methane hydrocarbon emissions from a northern midlatitude forest, L53^1^Chen,M^1994^6^Validation and Adjustment of Precipitation Simulated by CCM2/BATS over the Continental United States^M.MS.^University of Arizona^86^Thesis^^^Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP)^^^^^^^101^^^^^^^^^^^^Atmospheric Sciences^Dickinson, Robert E.^Dickinson, Robert E.^DE-FG02-91ER61216Q@g'5ErsTPYQ@g'5E COA^100^This study compares frequency, intensity and amount of precipitation simulated by NCAR CCM2/BATS with those observed DP over the continental United States. The emphasis is placed on both spatial and temporal variations. The analysis indicate GQs that: a) The model simulates the seasonal variation of daily intensity reasonably well, while the seasonal variation of Rfrequency is poorly produced. b) The model underestimates the amplitude of intensity, overestimates the amplitude of frequ Sency, and distorts the distribution of phase in diurnal variations. c)The simulated maximum hourly precipitation has almos Tt the same range as is observed. However, the model fails to simulate the overall pattern of maximum hourly precipitation, U maximum wet and dry periods from observations. d)The model overestimates the frequency of hourly precipitation by a factoVr of 13-48 and underestimates intensity by about 90%.These results demonstrate a necessity to adjust simulated precipitatiWon for realistic surface simulation. After adjustment, the simulated intensity is in much closer agreement to the observed value.a low carbon future with as little loss of output as is possible. The principal policy option that a government haY54^1^Delaney,Paul^1991^6^Sensitivity of Atmospheric Radiation to Temperature, Water Vapor and Ozone Profiles^M.S.^UniversiZty of Maryland at College Park^23^Thesis^^^Quantitative Links^^^^^^^103^^^^^^^^^^^^Meteorology^Ellingson, Robert G.^Ellingson, Robert G.^DE-FG05-90ER60971asing CO2 production through utilization of carbon intensive fossil fuels in a nation's e\A^102^The sensitivity of the longwave spectral radiance incident on the surface to uncertainties in the measurement of tem]perature, water vapor and ozone have been examined with the use of the line-by-line radiation code FASCODE2. Spectrally av^eraged results at one wavenumber resolution were obtained for simulated random and systematic errors in the meteorological_ data under midlatitude summer conditions. As expected, temperature errors dominate the uncertainties in the opaque region`s, whereas water vapor errors dominate the sensitivity in the atmospheric window. In general, the radiation field is most asensitive to uncertainties in water vapor, followed by temperature, tropospheric ozone then stratospheric ozone. Systematibc errors dominate radiance uncertainties, with reasonable random errors in the meteorological data resulting in radiance ejcrrors that are of the of 0.25 to 0.5 the magnitude of the systematic effects. The maximum effects of systematic errors on dthe fractional radiance error at any spectral location in the 5 to 20 micron region is the order of 2% per degree Kelvin and 1.2% per percent water vapor mixing ratio error for temperature and water vapor uncertainties, respectively.ime and hof55^1^Han,Dejiang^1993^6^Derivation of Cloud Fraction from Surface-Based Longwave Flux Observations^M.S.^University of Marygland at College Park^18^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^105^^^^^^^^^^^^Meteorology^Ellingson, Robert G.^Ellingson, Robert G.^DE-FG05-90ER61075t solution difficult, this dissertation develops procedures for determining boEA^104^Theoretical studies have shown that cloud geometrical factors have a significant impact on longwave fluxes and heatiHj41^1^Morris,Gary Allen^1994^6^Demonstration and Evaluation of Trajectory Mapping^Ph.D.^Rice University^100^Dissertation^^^Graduate Fellowships for Global Change^^^^^^^77^^^^^^^^^^^^Space Physics & Astronomy^Few, Arthur, and Mark Schoeberl^WohlplA^76^The problem of creating synoptic maps from asynoptically gathered data has prompted the development of a number of scjmhemes. Most notable among these schemes are the Kalman filter, the Salby-Fourier technique, and constituent reconstructionmn. This thesis presents a new technique, called trajectory mapping. Trajectory mapping employs a simple model of air parcelo motion to create synoptic maps from asynoptically gathered data. To assess the applicability of the technique, four sourcpes of trajectory mapping errors were analyzed. The analysis revealed that 1) the computational error is negligible; 2) meaqsurement uncertainties can result in errors which grow with time scales on the order of a week; 3) isentropic approximatiorns lead to errors characterized by time scales of a week; and 4) wind field inaccuracies can cause significant errors in isndividual parcel trajectories in a matter of hours. All the studies, however, indicated that while individual trajectory etrrors can grow rapidly, constituent distributions, such as those depicted in trajectory maps, are much more robust, maintauining a high level of accuracy for periods on the order of several weeks. The trajectory mapping technique has been succesvsfully applied to a variety of problems. First, trajectory mapping was employed in the study of dynamical wave-breaking evwents. Second, trajectory mapping was applied in satellite data validation studies, both for the determination of instrumenxt accuracy and precision. Third, trajectory mapping was used to assess the accuracy of the meteorological wind fields. Sucyh demonstrations imply that trajectory mapping will become an important tool in answering questions of global change, particularly the issue of ozone depletion.@!Ε(:T89U !Nq6,]EIK>?÷gggfIaԞ,{42^1^Everham,Edwin Mckay^1994^6^Hurricane Disturbance and Recovery: An Empirical and Simulation Study of Vegetation Dynami|cs in the Luquillo Experimental Forest, Puerto Rico^Ph.D.^State University of New York at Syracuse^278^Dissertation^^^Graduate Fellowships for Global Change^^^^^^^79^^^^^^^^^^^^College of Environmental Science and Forestry^Hall, Charles A.S.^Wo~A^78^Hurricanes and other catastrophic wind events impact forests over most of the globe. These disturbances are predicted to increase in frequency and intensity if ocean temperatures rise as the result of global warming. I examined spatial patterns of damage and the factors that influence these patterns, and the resulting dynamics of recovery in a subtropical wet forest following hurricane disturbance. I developed an approach to modeling disturbance dynamics in which any point in geographical space can be represented as a position in a multiple gradient space of abiotic factors; and disturbance and recovery are quantified as movements within this gradient space. Spatial pattern analysis indicates a significant clumping of hurricane damage. Canonical correlation analysis is used to compare the relative influence of abiotic factors to biotic factors in determining the severity of damage. Spatial patterns of hurricane damage are most strongly correlated to biotic factors, i.e., species of trees. Recovery is quantified in terms of vegetation community dynamics, rates of biomass accrual, and restructuring of the canopy; and is predicted based on gradients of abiotic factors and severity of hurricane disturbance. A two-dimensional gradient space of damage severity, quantified as structural damage (percent of stems downed) and compositional damage (percent of stems killed), is effective in delineating the two major paths to recovery: regeneration (sprouting of surviving trees) and recruitment (establishment of pioneer species). A three-dimensional gradient space, of structural damage and simulated light and soil moisture, allows prediction of rates of biomass accrual. Post-disturbance biomass increases are maximized under high levels of light and moderate levels of soil moisture and damage. The vertical restructuring of vegetation is associated with community dynamics of recovery, as predicted by damage severity, and by light available to the understory, as associated with topographic position. These responses are integrated into a spatially-explicit computer model (RECOVER) which simulates patterns of damage and recovery from a hurricane of a given intensity and track. This model is used to investigate the implications of changing the hurricane disturbance regime.S H:#;T43^1^Kearney,Anne Regina^1993^6^Promoting Ride Sharing: The Effect of Information on Knowledge Structure -- A Cognitive Perspective^M.S.^University of Michigan^99+^Thesis^^^Graduate Fellowships for Global Change^^^^^^^81^^^^^^^^^^^^School of Natural Resources and Environment^DeYoung, Raymond, and Stephen Kaplan^Wohlpart, A.^DE-AC05-76OR0003305-76OR00033v5A^80^Transportation sources are a dominant source of many air pollutants which contribute to environmental problems. They contribute 70% of carbon monoxide emissions, 45% of the nitrous oxides, 34% of hydrocarbon emissions, and 73% of lead emissions (EPA, 1991). These pollutants contribute significantly to ozone depletion, global warming, and acid rain, as well as cause many adverse health effects (Graedel and Crutzen, 1990; Schneider, 1990). A major component of transportation-related emissions can be attributed to work-related trips. The length and duration of these trips has continued to grow and greatly reduces any overall pollution reduction achieved through improved auto efficiency and cleaner fuels (Schreffler and Kuzmyak, 1991; EPA, 1991). The 1990 Amendments to the Clean Air Act were designed to address this problem by mandating the implementation of transportation control measures to reduce work- related vehicle trips. Specifically, all employers with at least 100 employees who are located in areas where emissions levels are above a set standard are required to implement a trip reduction program. However, while economic-based programs have often been successful at the macro-level (e.g., utilities, large manufacturers), they have generally failed to affect long-term changes at the micro-level (i.e. the individual energy consumer) (Dennis et al., 1990). Energy users have failed to adopt energy-conserving technology even when it is highly cost-effective (Ross and Williams, 1981) and the adoption of energy conservation practices has been described as unpredictable (Yates and Aronson, 1983). Behavioral changes which do occur are usually at the minimal acceptable level and discontinue when the economic incentive is removed (Cook and Berrenberg, 1981). Certainly for this category of programs, the rational economic model is not a good description of individual behavior; reliance on this model is likely to continue to produce programs and strategies which are ineffective. It appears unlikely that the rational-economic model can provide a useful framework for promoting energy conservation among individual consumers. A more descriptive model of decision-making has been proposed by Kaplan (1991) and is based on what is known about human cognition, human behavior, and human evolution. While this model recognizes that economic incentives are one factor in the decision- making process, emphasis is also placed on the role of knowledge in the decision-making process. Support for this position is derived from numerous other studies pointing to the importance of knowledge and the impact of a lack of knowledge when making decisions (e.g., DeYoung, 1988-89; Weigel and Amsterdam, 1976). It is hypothesized that this knowledge-based model will prove useful for the examination of individual decision-making with regards to employee ride-reduction behavior. The use of case studies or narratives (or "stories" as they will be referred to in this paper) which provide interesting, vivid, concrete, and personalized information has been suggested as an effective way to transfer information (Monroe and Kaplan, 1988). The characteristics of a good story (e.g., coherence, vivid and concrete detail, a sense of mystery) readily encourage a depth of cognitive processing which makes it likely that the information will be used when making future decisions. Stories have great potential for educating people about phenomena which cannot be directly experienced and for offering behavioral solutions to environmental problems. This study will use Kaplan's (1991) knowledge-based decision-making model to explore the impact of knowledge on attitudes and intended behavior towards carpooling. The model predicts that the knowledge an individual has about a particular subject has a significant effect on his/her decisions. In general, people with little or no knowledge about a behavior (or consequences of a behavior) will tend to avoid that behavior. People with a well developed knowledge structure about a particular behavior will feel more confident in their ability to carry out the behavior and will thus be more likely to engage in that behavior. This assumption is supported by empirical studies on the differences between solo drivers and users of alternative transportation (e.g., public transit, carpools). These studies (covered in the Literature Review) suggest that a major reason why drivers will not switch to alternative modes of transportation is because they lack information on how to switch and how to deal with problems which may be encountered while using an alternative mode. Another purpose of this study is to compare two different information campaigns on their effectiveness in imparting knowledge about carpooling to the study participants. Studies (covered by Literature Review) show that pallid, relatively abstract information (e.g., factsheet, factual brochures) are not very effective at transferring information. In contrast, using stories to transfer information may be very effective. In this study, a story-based information campaign will be compared to a factual-based information campaign. Both of the groups receiving the information campaigns will be compared to a control group. Carpooling was chosen as the target behavior because it traditionally has a low level of adoption and because of its wide applicability (e.g., as compared to public transit). Carpooling has been shown to be an effective means of reducing employee vehicle trips, thereby reducing environmental degradation due to commuting (EPA, 1991).+%K-/avR,C=44^1^Zhang,Qing^1990^6^Test of Transilient Turbulence Theory Against a Field Experiment^M.S.^University of Wisconsin - Madison^88^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^83^^^^^^^^^^^^Atmospheric and Oceanic Sciences^Stull, Roland B.^Stull, Roland B.^DE-FG02-92ER61361^@6j)PM lSf5٨@6j)PM lSf5٨@6j)PM lSfA^82^A simple 1-dimension grid-point boundary-layer simulation model based on transilient turbulence theory is tested against BLX83 experiment data. Transilient coefficients are parameterized using a simplified form of the total kinetic energy (TKE) equation instead of Richardson numbers. The model is absolutely numerically stable. May 28, 1983, a cloudless day with sufficient measurements, was chosen as the case-study day. The early morning radiosonde sounding is used to prescribe the initial conditions. Surface heat and moisture flux from an aircraft and flux tower, and surface geostrophic wind, thermal wind and horizontal temperature gradient are computed from surface temperature, pressure, and wind data from portable automated mesonet (PAM) stations, and are used to prescribe the forcings and boundary conditions on the model. Subsidence calculated from horizontal divergence is prescribed at the top of the model. Simulated potential temperature and specific humidity profiles compare well with actual radiosonde and aircraft soundings. Modeled heat flux decreases linearly with height as expected. Moisture flux profiles show a maximum near the top of the mixed layer (ML), also expected. There is no explicit forecast equation for ML depth z{-i} in the transilient model, yet the simulation exhibits a growing ML with entrainment. Modeled z{-i} is between radiosonde and aircraft soundings and lidar measurements. Modeled surface potential temperature and specific humidity evolution are close to the PAM II and radiosonde observations. A nonlocal spectral decomposition of the flux at different levels indicates that most contributions of the total flux at height Z are made by the eddies with size Z.98d#7Gp[W>x+(kV;3 zHE.ཇ_j[DŽ5<"p_`/Bcs203^1^Santoso,Edi^1993^6^A Wind-Profile Relationship for the Unstable Surface-Layer/Mixed-Layer System^M.S.^University of Wisconsin - Madison^59^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^369^^^^^^^^^^^^Atmospheric and Oceanic Sciences^Stull, Roland B.^Stull, Roland B.^DE-FG02-92ER61361^٨@6j)PM lSf5٨@6j)PM lSf5٨@A^368^Simple expressions for wind-speed, M, profiles in a convective statically-unstable surface-layer/mixed-layer system are derived empirically. The wind-speed profiles are consistent across the top of the surface layer. Wind shear decreases rapidly with height, z, in the surface layer and becomes negligible at the top of the surface layer and in the mixed-layer interior. Thus, one may assume zero wind shear as a boundary condition and definition for the top of the surface layer. The depth of the surface layer, z{-s}, and the wind speed in the mixed layer interior, M{-ML}, can then be estimated. For the surface-layer/mixed-layer system, it is hypothesized that z{-s} and M{-ML} may become relevant height and velocity scales in a similarity relationship, formulated as M/M{-ML} = f(z/z{-s}). Wind-speed data collected during the Minnesota atmospheric boundary-layer experiment are used to develop and evaluate alternative forms of the wind-speed profiles. All the data were measured during the late morning or mid afternoon, when the surface heat flux was positive and the depth of the mixed layer was nearly constant. Wind speeds near the surface increase rapidly with height, then become nearly constant in the mixed layer interior. Wind directions are nearly constant with height, with variations mostly less than 5 degrees for winds near the surface, and only some greater than 10 degrees for winds in the mixed layer. Based on close agreement with the data, there are two functional forms adopted in the surface layer (z z{-s}): M/M{-ML} = {{(z/z{-s}){+A}{}exp[A(1-z/z{-a})] with A = 0.0975 and M/M{-ML} = (z/z{-s}){+{{A(1-z/z{-s}){}} with A = 0.0840. Above the top of the surface layer (z > z{-s}), the wind speed is simply equal to M{-ML}. These expressions give good agreement to the observations and approximate the data to within a few percent. The average depth of the surface layer, z{-s}, is found to approach the traditional definition of z{-s} = 0.1*z{-i} (the depth of the mixed layer), but the relationship is weakly correlated. It is also found that the surface vertical momentum flux is highly correlated with M{-ML}{+2}, as expected. The mixed-layer drag coefficient value is found to be Cd{-ML} = 0.0014. While the Businger-Dyer formula that is extrapolated to the mixed-layer interior deviates when the height approaches the top of the surface layer, and usually is in error over all of the mixed layer, the functional forms proposed here can represent wind-profile data quite well within 99.9% of the whole surface-layer/mixed-layer domain. The functional forms above are not recommended for use below z = 1m, where they fail to represent the bottom portion of the log wind profile. This approach also does not work well when there is not a well-mixed layer of uniform wind speed, such as occurs with very weak convection and strong winds.s. y32g￳#>~g>J-?W46^1^Schrieber,Kelly M^1994^6^Observations of Surface-Layer Characteristics and Their Relationship to Boundary-Layer Cumulus^M.S.^University of Wisconsin - Madison^67^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^87^^^^^^^^^^^^Atmospheric and Oceanic Sciences^Stull, Roland B.^Stull, Roland B.^DE-FG02-92ER613618]agu]6h$>xz+ A^86^The subject of subgrid scale heterogeneity is one which has continued to pose problems for the numerical modeling community. Observations of meteorological and land use conditions which may account for these subgrid variations in the case of fair weather boundary layer cumulus (BL Cu) are presented. Clear sky cases are examined from aircraft data from the HAPEX field experiment of 1987, in order to eliminate any further heterogeneities which may be caused by cloud shading, enabling a more accurate assessment of the relationship between atmospheric conditions and the underlying surface. To account for the physical processes involved in the formation of non-precipitation BL Cu, buoyancy and moisture variables are chosen. The virtual potential temperature and lifting condensation level (LCL) are calculated for each data point along the surface-layer flight path of the aircraft. The path is divided into segments according to general surface type categories, and the resulting segments are examined. The original heterogeneous surface characteristics can later be obtained by a weighted average of the homogeneous segment characteristics. Joint distributions of virtual potential temperature and LCL are presented and evaluated. These distributions are found to be primarily mono-modal over relatively homogeneous ground-surface subdomains, and exhibit a sharp peak which tails off quickly to a finite end. The mean value for each distribution is found to be representative of the desired characteristics. It has been determined that distributions of LCL and virtual potential temperature over homogeneous land surfaces are mono-modal and remain fairly consistent over time. This quality is therefore one which can be parameterized and provide reliable information about BL Cu onset time and coverage. The information required is readily available from both routine measurements and normal model output. Sub-grid variability of surface type can be obtained from satellite inventories and cataloged for future model use. Finally, a conceptual model for a simple cumulus parameterization is presented. Based on the calculated LCL and virtual potential temperature values for a given homogeneous patch, the cumulus cover can be diagnosed by comparison with an averaged area sounding. One would expect to find either the LCL to be higher than the measured inversion height (dry conditions), or the virtual potential temperature to be cooler than the environmental sounding values (non-buoyant), for all of the clear-sky cases presented. It appears initially that this conceptual model was successful for the cases examined here.0XYxQ'=NXO`f >}47^1^Schmitt,Christina C^1990^6^The Effects of Surface Temperature and Clouds on the CO{-2} Forcing^M.S.^Colorado State Un iversity^114^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^89^^^^^^^^^^^^Atmospheric Science^Randall, David A.^Randall, David A.^DE-FG02-89ER69027^alPl{E\Q]0 ^#,Ofg~O~l`{?8?integrals to time-step the prognostic equations. Multigrid methods are used to solve the diagnostic equations for the stre?am function and velocity potential. The model is compared with the Arakawa-Lamb shallow water model and the NCAR spectral @transform shallow water model using the suite of seven test cases proposed by Williamson. The model performance characteriAstics are presented. The test cases show that the evolution of the fields is independent of the relative orientations of tBhe computational grid and the flow pattern. This is particularly true when flow is directed over the pole of the grid. AlsCo, the new model is tested using a Rossby-Haurwitz wave as initial conditions. The initial disturbance breaks down towards lower wavenumbers, but remains symmetric across the equator.YF3u晍OIk*]G1ivi]i1<,B.@e'">E50^1^Cripe,Douglas G^1994^6^Investigation of GCAPE Quasi-Equilibrium in the Midlatitudes^M.S.^Colorado State University^23F0^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^95^^^^^^^^^^^^Atmospheric Science^Randall, David A.^Randall, David A.^DE-FG02-91ER61363^;sc{r`lS]Y]g~yDgWuguŞ݇냾;Wc,]yg]"]qGEnHA^94^Lorenz (1955, 1978, 1979) developed the concept of the "moist available energy" (MAE) of the atmosphere. This he defiIned as the portion of non-kinetic energy (NKE) available for conversion to kinetic energy (KE). Randall and Wang (1992) anJd Wang and Randall (1994) showed that it is possible to consider the component of the MAE that resides in the vertical strKucture of the atmosphere as a "generalized convective available potential energy" (GCAPE). Using data from the tropics, thLey tested the GCAPE quasi-equilibrium hypothesis (Arakawa and Schubert, 1974) which asserts that cumulus convection "consuMmes" GCAPE as quickly as it is produced by large-scale (non-convective) forcing such that the convectively active atmospheNre remains close to a state of conditional neutrality. The main purpose of this study is to also investigate the GCAPE quaOsi-equilibrium hypothesis, only this time in a midlatitude setting. This is a tougher test of the hypothesis given the sigPnificantly larger temperature and moisture fluctuations resulting in a stronger large-scale forcing in the midlatitudes, cQompared with the tropics. Data recently made available by the Atmospheric Radiation Measurement (ARM) program has been useRd. This new data comes from radiosonde measurements collected at ARM's Cloud and Radiation Testbed (CART) site located in Snorth-central Oklahoma during Intensive Operation Periods (IOPs) run periodically throughout the year. Since this is one oTf the first studies to make extensive use of this data, a further goal was to evaluate the quality of the wind and thermodUynamic measurements being produced by the CART site. Additionally, analysis data from the Mesoscale Analysis and PredictioVn System (MAPS) was used, both as a check on the reasonableness of the ARM data, and also to detect any possible errors in the MAPS model output.]qwoeW}~Lwi8§9qdb?_wϏO}];?F>>}=wX51^1^Gleckler,Peter John^1993^6^The Partitioning of Meridional Energy Transport Between the Ocean and the Atmosphere^Ph.D.Y^University of California at Davis^160^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^97^^^^^^^^^^^^Land, Air & Water Resources^Weare, Bryan C.^Gates, W. Lawrence^W-7405-ENG-48^=?T8 ??>>=}gi-Ǒ}}zc:'?[A^96^The partitioning of meridional energy transport between the ocean and the atmosphere is a fundamental feature of the \climate system, and unfortunately one that remains poorly understood. Observationally-based estimates of atmospheric and o]ceanic meridional energy transport (respectively, AMET and OMET) resulting from various methods have been intercompared. E^nergy fluxes at the top of the atmosphere and at the ocean surface have also been studied because they are required by sev_eral methods used to estimate meridional energy transport. The resulting intercomparison has demonstrated that estimates o`f oceanic and atmospheric energy transport are inconsistent with one another. The uncertainties associated with OMET estimaates made with several methods have been established, but uncertainties in AMET estimates appear too complex to accuratelyb quantify. Much of this study has focused on ocean surface energy fluxes because annual mean estimates of AMET and OMET coculd be inferred if they were accurately known. Two methods have been established to improve our understanding of OMET (andd thus indirectly AMET). Both involve combining the same independent data and their associated uncertainties. All evidence esuggests that the most commonly cited estimates of Northern Hemisphere AMET based on radiosonde data are systematically tofo low. Lesser known estimates which make use of dynamical constraints are much more consistent with the various independengt estimates of OMET. At most latitudes in the Southern Hemisphere, it is not even clear whether the global ocean OMET is nhorthward or southward. Meridional energy transport has also been examined in three atmospheric GCM simulations. There are iconsiderable differences among the various models, particularly in the Southern Hemisphere OMET. It has been demonstrated jthat the implied transports in the models are strongly linked to the simulated cloud radiative forcing. The results of thiks study suggest that the most practical way to significantly improve our understanding AMET and OMET is with a small numbelr of strategically placed high quality hydrographic transects. It has been recommended that the utility of the methods devmeloped in this research which combine independent observationally-based data and their estimated uncertainties be considered in the planning of future global climate research programs..xOOGX_lb̬nrcy Ӻ87!o52^1^Rosa,Charles H^1993^6^Modeling Investment Uncertainty in the Costs of Global CO{-2} Emission Policy^Ph.D.^University pof Michigan^126^Dissertation^^^Graduate Fellowships for Global Change^^^^^^^99^^^^^^^^^^^^Industrial and Operations Engineering^Birge, John R.^Wohlpart, A.^DE-AC05-76OR00033H&]{Ξy9Cϡovoo>ϟYm$l/OrA^98^The dissertation investigates how the United States economy will evolve during the next 110 years if policies are impslemented which limit the production of carbon dioxide as a by-product of economic activity. Increased concentrations of attmospheric carbon dioxide, a principal determinant of terrestrial weather patterns, have led many to conclude that governmeuntal intervention is necessary to induce the world's economy to rely less upon carbon based fossil fuels. Many deterministvic macroeconomic models have been developed to try and determine what specific policies are necessary to cause this shift waway from fossil fuel use as well as what the cost of such measures are in terms of lost economic output. This dissertatioxn develops a nonlinear stochastic macroeconomic model with continuously distributed random variables that determines optimyal policy while explicitly modeling the uncertainty inherent in new technology development and exhaustible resource explorzation. It compares the optimal policy developed in this stochastic model with non-optimal policy derived under the assumpt{ion of a certain future, and measures the resulting improvement in economic performance. Because the stochastic model with| continuously distributed random variables is very difficult to solve, this dissertation bounds the true solution. It uses} a parallel implementation of a nonlinear decomposition algorithm to obtain an upper bound and develops a new lower boundi~ng method based on the linear response function technique for stochastic linear programs to derive a lower bound. The quality of the resulting bounds is explored as well as the benefits of parallelization as a means of improving solution times.6PhBƹO%-,Sf5٨@6j)PM o3K_L+ѪcB''uIS돇Bmƀط>5~ë#8P5\'S yng rates, yet most models used in climate studies employ rather crude approximations of these effects. This study was designed to determine the possibility of estimating such geometrical effects with the use of surface-based infrared flux observations as might be obtained during the Atmospheric Radiation Measurement (ARM) program. The results show that pyrgeometer measurements can be used to determine the effective cloud fraction in a manner useful for geometrical parameterizations if the error variance of the observations is less than about 5 Watts per meter squared. In general, the uncertainties associated with such determinations increase with increasing water vapor burden. Overall, the pyrgeometer error restrictions are difficult to meet, but they may be possible with careful monitoring and control.~y(ο>ۧb?=H/7172^1^Santer,Benjamin David^1988^6^Regional Validation of General Circulation Models^Ph.D.^University of East Anglia^375^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^309^^^^^^^^^^^^School of Environmental Sciences^Wigley, T.M.L.^Wigley,e modelled soil organic material's turnover times, which range from decades to millennia, as a binary system having active and passive components. CO{-2} fertilization, the plant net primary productivity increase observed at elevated CO{-2} lev184^1^Harrison,Kevin Geyer^1993^6^The Impact of CO{-2} Fertilization, Changing Land Use and N-Deposition on Soil Carbon Storage^Ph.D.^Columbia University^134^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^332^^^^^^^^^^^^Lamont-Doherty EarA^331^Fossil fuel combustion and changing land use have increased atmospheric and oceanic carbon inventories less dramatic:ally than expected. This discrepancy has been termed the "missing sink." CO{-2} fertilization and N-deposition processes c84^1^Prior,Stephen Arthur^1993^6^Cotton Root Response to Free-Air CO{-2} Enrichment^Ph.D.^Auburn University^136^Dissertati9on^^^Carbon, Climate, and Vegetation^^^^^^^149^^^^^^^^^^^^Agronomy and Soils^Rogers, Hugo H.^Rogers, Hugo H.^ER60001^Agron61^1^Najjar,Raymond G.^1990^6^Simulations of the Phosphorus and Oxygen Cycles in the World Ocean Using a General Circulation Model^Ph.D.^Princeton University^190^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^147^^^^^^^^^^^^Geological & Geophysical Sciences^Sarmiento, Jorge L.^Sarmiento, Jorge L.^DOE MM-19X-27405C^|sq_}l6-QWOyO8מ?q_;Z;64^1^Arsky,Natalie^1994^6^Prediction of the Generalized Ecotypes with COLA GCM Using Four Different Bioclimatic Schemes^M.S.^University of Maryland at College Park^22^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^117^^^^^^^^^^^^Meteorology^Baer, Ferdinand^Baer, Ferdinand^DE-FG02-94ER61746ώߞwvw"*8OyO?; Aߺ><gĿ1A^116^The problem of interactive coupling of the AGCM to the biospheric model is examined. Four different bioclimatic schemes, which relate the atmospheric parameters like annual temperature and precipitation to the vegetation distribution, were implemented. The schemes were applied to two global climate data sets. One represents the result of the COLA (Center for Ocean-Land-Atmosphere Interactions) model R-15 version simulation of the present-day climate (without coupled ocean). Ten years monthly averages of near-surface temperature, total precipitation, soil wetness, net long-wave radiation and short-wave radiation absorbed at the surface were used for schemes calculations. Another data set represents climatological temperature and precipitation data (Jaeger data set, NCAR). The main result is that all four models are able to reproduce the main features of the vegetation distribution. Thus, the schemes can be used as a first step in coupling of atmospheric GCM with biosphere, e.g. "interactive biosphere". In addition, they can be a useful tool in interpreting of the GCM results of future and past climates simulations and a diagnostic tool for verification of the model performance in a simulation of the present-day climate.i q8N-?W]Vqc~3ﳻk/oOj}]p`߳>?865^1^Zhang,Bing^1993^6^Use of Taylor Expansion in Computation of the Simplest Spectral Barotropic Vorticity Equation^M.S.^University of Maryland at College Park^29^Thesis^^^Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP)^^^^^^^119^^^^^^^^^^^^Meteorology^Baer, Ferdinand^Baer, Ferdinand^DEFG0591ER61219^qf&mp߰* ;  \ GM@A^118^Time integration is the basic part of the computation of meteorologic forecast models, but the time step is constrained by stability consideration, CFL condition must be satisfied for linear problems. The time steps are very short for high frequency components, this makes the integration procedures extremely time-consuming, especially for climate models. The current popular numerical integration scheme for time integration is three time-level leapfrog scheme which uses the first order derivative at the mid-level, we will refer this method as the regular leapfrog scheme. In this paper, a system of the simplest spectral barotropic vorticity equation in channel domain is experimentally computed by using Taylor's expansions of time dependent variables so that higher derivatives are included in computing the values at next time level. Taylor's expansion is applied for two computational schemes: one is "leapfrog" with the derivatives evaluated at the mid-level, the other is the two time-level forward scheme with the derivatives evaluated at level one, at which all variables values are considered as known, and the predicted outputs are given at level two. The experiment shows that on the average, when certain number of derivatives are included in the expansions, the integration time step can be more than 6 times of those given by the regular leapfrog scheme without losing any accuracy. This results tells us that it is possible to integrate the equations with a much higher time step by rewriting the forecasting equations in their Taylor's expansion forms. Although Taylor's expansion forms are usually much more complicated compared with the forms of the regular leapfrog scheme, time integration can still be fastened if each term in Taylor's expansion is assigned to one processor of the Massive Parallel Processors. The deal is the lose of simple expression form in exchange of the gaining of computational speed when MPP is used. In addition, the simple expansion form of the regular leapfrog scheme (several integration time steps are combined into one expression) is tested. Compared with Taylor's expansion forms, it will take about two orders magnitude higher computation times for the same increase of integration time step. This shows that the perspective of making use of Massive Parallel Processors with the use of Taylor's expansion forms are brighter..zǐ׿;~gO瞶Ogp>x_p,66^1^Charney,Joseph J^1992^6^Heating Rate Variability in Radiation Codes When Subjected to Different Vertical Discretizations^M.S.^University of Maryland at College Park^43^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^121^^^^^^^^^^^^Meteorology^Baer, Ferdinand^Baer, Ferdinand^DE-FG05-90ER61075yy7c8?g3ۨiU ){ܐZIeiW }r@i%A^120^A collection of seven radiation codes was acquired from various organizations and intercompared. Their variability with respect to each other was determined when performing heating rate calculations on different distributions of vertical levels. Specifically, two vertical discretizations with 30 and 18 levels were intercompared. Some significant differences were found to exist by performing simple statistical tests on the models. The statistical tests were based on sets of 100 heating rate calculations. Independent determinations were made at each model level. The parameterizations of water vapor absorptivities were found to cause the largest variability between the models. Other mechanical problems were highlighted and recommendations for future steps in the ongoing study were proposed.lSf5b3BvtqcZork at Albany^86^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^315^^^^^^^^^^^^Atmospheric Science^Wang, Wei-Chyung^Wang, 175^1^Zhong,Min^1994^6^The Greenhouse Effect in the Present Earth-Atmosphere Climate System^M.S.^State University of New Y308^1^Brakke,Mary P^1989^6^Gas Exchange and Growth Responses of Citrus Trees to Partial Irrigation, Soil Water, and Atmospheric Conditions^Ph.D.^University of Florida^181^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^609^^^^^^^^^^^^Agronomy^Allen, Leon H., Jr.^Allen, Leon H., Jr.^DE-AI01-81ER60001Q:xV,ǞvC{PPMt}q~y}vw" fǞin the cloud-radiation parameterization.thetic Response of Soybeans: Model Development and Elevated Carbon Dioxide Experiry to the conclusion of Wigley and Raper (1990a).^^^Carbon, Climate, and Vegetation^^^^^^^528^^^^^^^^^^^^Agricultural Engineering^Jones, J.W.^Allen, L.H., Jr.^DE-AI01-81ER60001^*4}ߞ3UgxwƱLֽ3ޣ-}ޏ G=v&;311^1^Roy,Brian L^1988^6^Development and Evaluation of an Adaptive Control Procedure for Carbon Dioxide Control in Environmental Growth Chambers^M.Eng.^University of Florida^130^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^615^^^^^^^^^^^^Agricultural Engineering^Jones, Pierce H.^Allen, Leon H., Jr.^DE-AI01-81ER60001, DE-AI05-88ER69014}{>|oϾ72^1^Hussain,Mian W^1992^6^Effect of Elevated CO{-2} and Temperature on Sucrose Phosphate Synthase Activity and Carbohydrate Metabolism in Rice^Ph.D.^University of Florida^157^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^526^^^^^^^^^^^^Botany^Bowes, G.^Allen, L.H., Jr.^DE-AI05-88ER69014^>G?7𑟏dqoWH?o7<$ǂ~313^1^Kamuru,Freeman^1992^6^Ammonia Production by a Mutant Strain of _Anabaena variabilis_ and Its Contribution to Growth and Yield of Rice (_Oryza sativa_ L.)^Ph.D.^University of Florida^155^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^619^^^^^^^^^^^^Agronomy^Allen, Leon H., Jr., and S.L. Albrecht^Allen, Leon H., Jr.^DE-AI05-88ER690146-es#0>1ߊ(7tunity to consider not only the radiative balances at the top of the atmosphere but also the clear sky radiative fluxes. Tth Observatory^Broecker, Wallace S.^Broecker, Wallace S.^DE-FG02-91ER61247UmM~|: z!g!8G3~|ration with fixed sea-surface temperature), the OSU CGCM (in years 11-20 of a 20-year control integration, in which the tw305^^^^^^^^^^^^Chemistry^Zoller, William H.^Gaffney, Jeffrey S., and Nancy A. Marley^W-31-109-ENG-38, W-7405-ENG-36kى A^304^A field site was established at Frijoles Mesa in Northern New Mexico to study the tropospheric photochemical oxidant at a Remote Location in Northern New Mexico^Ph.D.^University of Washington^183^Dissertation^^^Atmospheric Sciences^^^^^^^169^1^De Bruyn,Warren J^1994^6^The Heterogeneous Chemistry of Carbonyl Halides, Haloacetyl Halides and Biogenic Sulfur Spe2ER61453ѐs>nz4m -m -¶nC٨@6j)PM lSflTz: Fp3)^NŐBgFK97^1^Little,Jackie^1994^6^Patterns of Recovery in a Riverine Mangrove Forest^Ph.D.^University of Tennessee^183^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^158^^^^^^^^^^^^Graduate Program in Ecology^Rennie, John^Emanuel, W.R.^DE-AC05-84A^157^This research forecasts the effect of variable hurricane intensity on mangrove forest structure and evaluates the role of species composition in recovery. Baseline data estimates were made along the Shark River in Everglades National Park, Florida, USA, in 1992, 32 years after Hurricane Donna ripped up the southwestern Florida coast. Hurricane disturbance and forest recovery were simulated in an individual-based model. Results were extrapolated to forecast the effects of two factors: windfall, in which 37.5%, 62.5%, and 87.5% of stand density is blown over; and species composition, in which plots were categorized according to dominance by species which stump sprout [_Avicennia germinans_ (AVGE) and _Laguncularia racemosa_ (LARA)] vs dominance by the species not capable of sprouting [_Rhizophora mangle_ (RHMA)]. Four stands were sampled along a 7 km transect adjacent to the Shark River and perpendicular to the path of Hurricane Donna. Mortality and recovery were inferred from diameter size-class density and basal area distributions. Analysis of the field data showed the presence of three cohorts post-hurricane recruits, and intermediate size class of stump sprouts and young survivors, and mature survivors of the hurricane. A major conclusion of the field data analysis was that sprouting and shade tolerance are effective recovery mechanisms that unexpectedly boost residual stem density in highly disturbed stands. To understand the structural patterns, plot data was back-calculated to prehurricane estimates and hurricane disturbance was simulated. The most  simple explanation for the observed structure, variable wind intensity, was supported for plots without stump sprouting. H owever, in plots with sprouting, the relationship between intensity, and recruits and sprouts was positive from low to mod erate intensity and leveled off from moderate to high intensity. The conceptual model that emerges is that hurricane distu rbance, regardless of intensity, is filtered through a "grid" of species characteristics, and it is these traits which mos t influences stand structure. The recovery mechanism in plots dominated by AVGE/LARA, was survival, particularly below-ground, and site retention by individuals who were established before the disturbance. In plots dominated by RHMA, recovery following moderate and intense disturbance depended on the establishment of new recruits.+@Go +Gye>M to understand their role in the upper tropospheric hydrologic cycle. This is primarily achieved with the aid of remote sensors. To extract information from remotely sensed data, it is necessary to understand how electromagnetic radiation interacts with cirrus ice particles. The work presented herein attempted to understand how ice particles of an arbitrary shape backscatter electromagnetic radiation at cloud radar wavelengths. The discrete dipole approximation (DDA) was applied to the backscattering of millimeter wave radiation by nonspherical ice particles. A simple analytical model of the DDA was developed to demonstrate the underlying physical principles and to understand the directional sensitivity of scattering. Backscattering by single particles was studied to test the use and validity of spheroidal models to model nonspheroidal hydrometeors which are characteristic of cirrus. Limitations of the Rayleigh approximation at millimeter wavelengths were also explored. It was found that for wavelengths on the order of or greater than 3 mm, spheroidal shapes adequately represent hexagonal columns and plates. The Rayleigh approximation for spheroids begins to break down for wavelengths below 3 mm if the particles have major dimensions which are typical of cirrus ice crystals. The sensitivity of backscattered radiation to variations in microphysical properties were examined, based on DDA calculations for ensembles of ice particles. The most important factor was found to be the median diameter of the third moment (_D{-m}_) of the ice crystal size distribution. In particular, if _D{-m}_ was relatively large, the contribution of small crystals (_i.e._ crystals whose major dimension was on the order of, or less than 100 m) was masked by the signal of the larger crystals which possessed major dimensions of greater than approximately 400 m. Simulations of effective radar reflectivity factor-ice water content relations (_Z{-e } - IWC_) were also presented. Comparison with available empirical relations indicate a functional dependence of the IWC o!n the number of large crystals (_i.e. D{-m}_) and also suggest a set of reasonable limits for the parameter _D{-m}_. Implications for the remote sensing of ice clouds at millimeter wavelengths were discussed.cussed.Gqoyӧus#ranspiration (ET) replaced and dry, 75% (1990) and 67% (1991) of ET replaced] on cotton root growth at two growth stages ($vegetative and reproductive). A new exposure method called free-air CO{-2} enrichment (FACE) was used to create large-scal%e test atmospheres in the field with minimal disturbance of plant microclimate. A portable soil coring system was designed&, constructed, tested and used to collect root soil samples. Soil root cores to a depth of 90 cm were collected within the' crop row (0 m) and interrow (0.25 and 0.5 m) to evaluate vertical and horizontal rooting distribution. Root systems (tapr(oot and attached laterals) were excavated to describe morphological patterns. Laterals were divided into four classes base)d on diameter size [Class 1 (1.0 mm<); Class 2 (1.0-1.5 mm); Class 3 (1.5-2.0 mm); and Class 4 (>2.0 mm)]. The effect of w*ater stress or its interaction with CO{-2} were generally nonexistent with respect to root density (length and dry weight)+. At the second sampling (reproductive), root weight per unit length was usually greater under water stress throughout the, soil profile. At the initial sampling (vegetative), whole profile root density (length and dry weight) and root weight pe-r unit length were usually increased under high CO{-2} at all horizontal positions. The positive effects of CO{-2} on thes.e measurements at the second sampling were limited to the 0.5 m position. At the first sampling, root dry weight density b/y depth increment were usually higher under FACE throughout the profile and at all horizontal positions, whereas increases0 in root length density were restricted to interrow positions. For most positions at the second sampling, enhancements in 1root weight per unit length and root length density occurred in the upper parts of the soil profile. At this period, FACE 2increased root dry weight density throughout the profile, especially at the interrow positions. Water stress had not effec3t on the taproot system (taproot plus laterals) at the initial period, but water stress at the second period resulted in r4educed length, volume, and dry weight in the second year. At both samplings, most of the taproot measurements (volume, dry5 weight, lengths, and tissue density) were increased due to extra CO{-2}. Similar responses were noted when taproot and la6terals were measured separately. Significant CO{-2} by water interactions were detected when lateral roots were partitione7d into classes based on diameter size. Interactions were detected in Class 1 (first sampling) and Class 3 (second sampling8). In all cases, the positive effects of added CO{-2} occurred under water stress conditions. Results from this study clearly suggest enhancement of root growth of cotton in an elevated CO{-2} atmosphere.矏3J`l/eTy_omy and SoilsR60001 to ARS-USDA^Agronomy and Soils}ߞwhQ?yd>&;:yc8g~;ould be sequestering some of this missing carbon. An improved understanding of disturbance and recovery carbon dynamics as99^1^Bremer,D J^1994^6^Transpiration from a Tallgrass Prairie Exposed to Elevated and Ambient Atmospheric CO{-2}^M.S.^Kans?as State University^110^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^161^^^^^^^^^^^^Agronomy^Ham, J.M.^Owensby, C.E.^DE-FG02-84ER60253-A018?^ό>M}hƀ_87=|s#ΟzAA^160^Increasing concentrations of atmospheric CO{-2} may influence plant-water relations in natural and agricultural ecosBystems. A tallgrass prairie near Manhattan, Kansas was exposed to elevated atmospheric CO{-2} using open-top chambers (OTCC's). Heat balance sap flow gauges were used to measure transpiration in ironweed (_Vernonia baldwini_ var. interior (SmallD) Schub.), a C3 forb; and on individual culms of big bluestem (_Andropogon gerardii_ Vitman) and indiangrass (_SorghastrumE nutans_ (L.) Nash), both C4 grasses, in each of three treatments: (1) CE (chamber enriched, 2x ambient CO{-2}); (2) CA (cFhamber ambient, no CO{-2} enrichment); and (3) NC (no chamber, no CO{-2} enrichment). Sap flow data were combined with meaGsurements of stomatal resistance and whole-chamber evapotranspiration (ET) to determine the effect of CO{-2} on water use Hat different scales. Because of frequent rainfall during the study, all data were collected under well-watered conditions.I Sap flow was reduced by 33% in ironweed, 18% in big bluestem, and 22% in indiangrass under CO{-2} enrichment. Elevated COJ{-2} reduced whole chamber ET by 23-27%. The environmental effect of the OTC reduced transpiration by 21-24%. Stomatal conKductance declined from 6.6 mm s{+-1} to 3.2 mm s{+-1} in big bluestem, and from 5.0 mm s{+-1} to 3.1 mm s{+-1} in indiangrLass, under CO{-2} enrichment. Whole-plant stomatal resistance to water vapor flux (rp) was calculated from sap flow measurMements and environmental data collected in the chambers. Whole-plant stomatal resistance in big bluestem increased from 10N3 s m{+-1} to 194 s m{+-1} under elevated CO{-2} during sap flow measurements. Whole-plant stomatal resistance was scaled Oto the canopy level, but consistently underestimated the canopy resistance calculated from whole-chamber ET data, indicatiPng that rp in big bluestem may not be representative of rp in other plants or species in the chamber. Elevated CO{-2} incrQeased whole-chamber canopy resistance more than scaled-up canopy resistance. Thus, elevated CO{-2} probably increases stomRatal resistance in other species in the OTC more than that of big bluestem. As atmospheric CO{-2} increases, CO{-2}-induced stomatal closure may alter plant-water relations and the water balance of an ecosystem.Sf5٨@6j)PM lSfT100^1^King,Anthony W^1986^6^Using Ecosystem Models to Predict Regional CO{-2} Exchange Between the Atmosphere and the TerrUestrial Biosphere^Ph.D.^University of Tennessee^273^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^163^^^^^^^^^^^^Graduate Program in Ecology^DeAngelis, D.L.^Emanuel, W.R.^DE-AC05-84OR21400PM lSf5٨@6j)PM lSf5WA^162^Ecologically sound models of the terrestrial biosphere are needed in the investigation of the Earth system and globaXl change. Traditional ecosystem models simulate many processes and dynamics relevant to the functioning of the Earth systeYm, but their application is limited by their local, small-scale, often site-specific nature. We address this limitation byZ deriving a method for predicting regional biosphere dynamics by extrapolation from smaller-scale ecosystem models. We use[ models of local ecosystem carbon dynamics to predict the seasonal exchange of CO{-2} between the atmosphere and terrestri\al ecosystems of 64N to 90N latitude. Monte Carlo simulation is used to integrate solutions of a tundra model and a conife]rous forest model across within-biome heterogeneity in the models' climatic driving variables. The product of the expected^ value of each model's output and the area of the region occupied by that biome or ecosystem type is an estimate of biome-_scale CO{-2} exchange. Regional CO{-2} exchange is the sum of the biome exchanges. Comparisons of the extrapolation's resu`lts with independent estimates of seasonal CO{-2} exchange and annual net primary production support the proposition that extrapolation of ecosystem models can be used to simulate regional biosphere dynamics.Xc,clz$>(N bthe ecological and climatological considerations, including areas of major agricultural productivity such as the Corn Beltc. This study investigated the relationship between temperature and precipitation over an 80-year period from 1905 to 1984 in the continental United States to see whether the climate tends to be wetter or dryer when it gets warmer. These past pae102^1^Bisbal,Evelin C^1987^6^Effects of Subambient and Superambient CO{-2} Levels on Growth, Development and Total Nonstrufctural Carbohydrates of Soybean^M.S.^University of Florida^144^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^520^^^^^^^^^^^^Agronomy^Allen, Leon H., Jr.^Allen, Leon H., Jr.^DE-AI01-81ER60001^}Ǟqfoo|׌u6-9h269^1^Boden,Thomas A^1985^6^An Internship with the Carbon Dioxide Information Center at Oak Ridge National Laboratory^M.Eni.^Miami University^115^Report^^^Information^^^^^^^505^^^^^^^^^^^^Institute of Environmental Sciences^Vankat, John L.^Farrell, Michael P.^DE-AC05-84OR21400q;8s2j߹}EtWEWtqZb߼~yޠ+]qؓy?Lx±<Þ̇4x;!k309^1^Campbell,William J,Jr^1986^6^Effects of Carbon Dioxide on the Physiology and Biochemistry of Photosynthesis in Soybelan^Ph.D.^University of Florida^181^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^611^^^^^^^^^^^^Agronomy^Allen, Leon H., Jr.^Allen, Leon H., Jr.^DE-AI01-81ER60001>do5tO8~m2;ub^Q6HhϏľώyP-?yzn221^1^Ahmed,Faisal Elgasim^1992^6^Heat Injury to Reproductive Development in Cowpea (_Vigna unguiculata_ (L.) Walp.) Undero Ambient and Elevated Carbon Dioxide Concentrations^Ph.D.^University of California at Riverside^100^Dissertation^^^Nationa l Institute for Global Environmental Change (NIGEC)^^^^^^^409^^^^^^^^^^^^Botany and Plant Sciences^Hall, Anthony E.^Hall, q214^1^Olaizola,Miguel^1993^6^Laboratory and Field Studies of Diatoxanthin Cycling and Non-Photochemical Fluorescence Quenc hing in Marine Phytoplankton (_Chaetoceros muelleri_, _Thalassiosira aestivalis_, _Phaeodactylum tricornutum_, diatoms)^Phs) CO{-2} concentrations. The objectives were to determine the effects of subambient and superambient CO{-2} concentration ton (1) seasonal pattern of dry matter distribution, leaf growth, and development stages, and (2) seasonal and diurnal patterns of total nonstructural carbohydrate (TNC) concentration. Morning and evening plant samples were taken at eight dates.vrue values. Determination of pH after additions of known amounts of strong acid to lake water were internally consistent ownly when done using the carbon dioxide equilibria calculation. A second observed phenomenon was that the alkalinity determined by the Gran linear extrapolation method was always greater than HCO{-3}{+-} ion concentration determined independently109^1^Eischeid,Jon K^1986^6^Precipitation Variations over Northern Hemisphere Land Areas and Major Wheat-Producing Regionsz: 1851-1980^M.S.^University of Massachusetts^195^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^402^^^^^^^^^^^^Geology and Geography^Bradley, Raymond S.^Bradley, Raymond S.^DE-FG02-85ER60316^^;?o+s2yNYߜYߛb|275^1^Fowler,David E^1985^6^An Internship with the Carbon Dioxide Information Center^M.En.^Miami University^34^Report^^^Information^^^^^^^517^^^^^^^^^^^^Institute of Environmental Sciences^Morgan, Hugh^Farrell, Michael P.^DE-AC05-84OR21400tous and important components of the troposphere at all the sites. The high reactivity of the biogenic compounds (isoprene181^1^Gale,William J^1988^6^Canopy Net Carbon Dioxide Exchange by Burned and Unburned Tallgrass Prairie^M.S.^Kansas State University^79^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^327^^^^^^^^^^^^Agronomy (Evapotranspiration Laboratory)^Kirkham, M.B.^Kirkham, M.B.^DE-FG02-84ER60253^^䀹wh'Yٜ.h4m qg^>F8,kǔqzWN-Oocarbons and Implications for the Oxidative Chemistry^Ph.D.^University of Washington^142^Dissertation^^^Atmospheric Scienc251^1^Manunta,Paolo^1995^6^Respiration and Growth of Sorghum (C{-4}) and Sunflower (C{-3}) Under Predicted Increased Night Temperatures^M.S.^Kansas State University^110^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^469^^^^^^^^^^^^Agronomy (Evapotranspiration Laboratory)^Kirkham, M.B.^Kirkham, M.B.^DE-FG02-84ER60253!qespn+'xX\$of8( T.M.L.^DE-FG02-86ER60397^O 1OQżs6@goC!c|ۺ;D!tqEM[Nߋ!,w=n183^1^Dutton,Todd H^1994^6^The Effects of Temperature, Atmospheric CO{-2} Concentrations and Arbuscular Mycorrhizal Populations from Two Disparate Biomes on Growth and Biomass Accumulation of 'Eureka' Lemon (_Citrus limon_ (Hort.))^M.S.^Arizona State University^38^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^330^^^^^^^^^^^^Botany^Martin, Chris^Acock, Basil, Leon H. Allen, Jr., and Bruce A. Kimball^DE-AI05-93ER61720;?瑏Wc3G͐&\瞥L}GvC>G 3hesis^^^Carbon, Climate, and Vegetation^^^^^^^277^^^^^^^^^^^^Earth, Atmospheric and Planetary Sciences^Stone, Peter H.^MacA^276^The interaction between trace shortwave radiative absorbers and the dynamical circulation is shown to be linearly university of California at Berkeley^202^Dissertation^^^Atmospheric Sciences^^^^^^^279^^^^^^^^^^^^Chemistry^Johnston, Harold^Wuebbles, Donald J.^W-7405-ENG-48~8<_'c'oߐq[!w=9wsQ]uCz;?N,ynk>~w?_[wcpw蝟מqؗ}Fs of the mean sea-level pressure (MSLP) fields simulated by three GCMs - the OSU two-layer AGCM(in a 10-year control integthere are few objective intercomparison studies to substantiate this. This study examines the regional and seasonal detailhow considerable disagreement in terms of important regional and seasonal details of their control run climatologies, but rmination of how successfully GCMs perform in simulating present-day climate. It is generally accepted that current GCMs sof experimental results can only be obtained by detailed validation of model control run results - e.g., by objective deteeriments, such as simulating the possible climatic effects of doubled or quadrupled CO{-2}. Confidence in the reliability A^308^General Circulation Models (GCMs) of the atmosphere and ocean have been used for performing a variety of climate expiogenic sources.yǔq,y_H~~w<'ߛwdwWQWYDGWN<>Gc~(?YG1~+?ve a large effect on tropospheric oxidation processes. Acetaldehyde, acetone and MEK were determined to have significant bne hydrocarbons at a given concentration. Therefore, even at small concentrations, biogenic nonmethane hydrocarbons can harelevant atmospheric parameters. This report also examines whether recognized anthropogenic influences are sufficient to explain recent measured trends in atmospheric ozone and temperature. An attempt is made to evaluate the chemical compositio n and temperature structure of the atmosphere before major human influence, termed the pre-industrial atmosphere. A compar and terpenes) results in greater rates of free radical chain reaction propagation than for typical anthropogenic nonmetha217^1^Glubczynski,A^1983^6^The Effects of Land Use on Soil Organic Carbon in Subtropical Forest Life Zones in Puerto Rico^M.S.^University of Illinois at Urbana-Champaign^81^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^398^^^^^^^^^^^^Forestry^Brown, Sandra^Brown, Sandra^EV-78-S-05-6047Hnwx[7 :?߯?of>.h£ q:?߮?o}dative state of the tropospheric was discussed for each location. Biogenic nonmethane hydrocarbons were found to be ubiquiions with freeze-up than did thawing degree-days with break-up. For several Canadian lakes studied, a 5 day variation in the date of freeze-up corresponds approximately to a 1 C change in temperature for the 30 days preceding this event. Future research should seek to obtain a wider distribution of lake ice datasets, as well as information on physical lake paasurements reported for other similar sites. The first simultaneous measurements of glyoxal, hydroxyacetaldehyde, methylgl277^1^Akkarappuram,Anto Francis^1988^6^Air-Sea Exchange Processes off the Carolinas During the 1986 East Coast Winter Storms - _GALE (Genesis of Atlantic Lows Experiment)_^M.S.^North Carolina State University^105^Thesis^^^Marine Transport^^^^^^^539^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Pietrafesa, Leonard J.^DE-AS09-76EV00902yt}A^198^noneY9<6㙟Ͽ<΃|[#y/}]q`o>d North American continental sites during 1989. The speciation and range of carbonyl compounds were compared to the few med with profiles from the previous study in an effort to obtain information on the nature of certain physical and chemical processes in the Neuse river estuary through time.regon State University^154^Thesis^^^Carbon, Climate, and Vegetation^^^^ 209^1^Suzuki,Marcelino^1994^6^The ARM Assay for the Measurement of Protistan Bacterivory Rates and Ammonium Regeneration EA^306^Concentration and stable isotopic measurements of tropospheric carbonyl compounds were made at three widely separaterformed at a later date. Activities of {+226}Ra, {+228}Ra, {+137}Cs, and {+40}K in the bottom sediments were measured by gamma spectrometry. Chloride concentrations in the interstitial waters were measured by ion chromatography. Six of the eight sampling locations are stations that were revisited from a previous study. Data profiles from these stations are compare36^4^noneylհ6-癏=gϿ|}<>Ϸyo5lM93qǘgqwA^397^Soil samples from forested and agriculture sites in three subtropical forest life zones were analyzed for soil organic carbon in an effort to determine the effects of land use and life zone on soil carbon content. In general, soil carbon was highest in the mature forest sites (70.6-125.6 t/ha, 0-50 cm deep), particularly those in wet forest life zones. Agric %nded solid and the colloidal organics was found to be linearly related to the amount of organic in solution. This relationunction. Regional monthly probabilities were then culled from the gridded set and averaged over the appropriate months to arrive at seasonal values. The seasonal probabilities were then subjected to several tests in order to describe temporal v 7ariability: trend tests utilizing the method of least squares; persistence tests using the simple autocorrelation functionth a trace metal (yttrium) and a suspended solid (silica gel). The distribution coefficient of the metal between the suspetritium input is overestimated in both hemispheres and compromised in the northern hemisphere by a lack of 1950's input. In modeling the input of {+90}Sr to the surface mixed layer we find that a vertical mixing rate of 1.5 cm/sec at the base of the mixed layer reproduces the observed time history. Given the vertical mixing calibration, the model predicts an averOR21400neq*}wc. W<~>Gߙ27ztF~>n&ź?~~8ކ87{7|c>#?}tigation of PANs: 1) long range transport of NO{-x} from urban locations with respect to seasonal frequency and magnitude,257^1^Zhao,Weining^1990^6^The Relationship Between Precipitation and Temperature over the Continental United States^M.S.^Oregon Graduate Institute, Global Change Research Center^125^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^481^^^^^^^^^^^^Environmental Science and Engineering^Khalil, M. Aslam K.^Rasmussen, R.A., and M.A.K. Khalil^DE-FG06-85ER60313^y}otrument control and data storage. The resulting 1.5 year continuous data set for PAN and O{-3} provided a first time inves307^1^Bisbal,Evelin Cabrera^1987^6^Effects of Subambient and Superambient CO{-2} Levels on Growth, Development and Total Nonstructural Carbohydrate of Soybean^M.S.^University of Florida^144^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^607^^^^^^^^^^^^Agronomy^Allen, Leon H., Jr.^Allen, Leon H., Jr.^DE-AI01-81ER60001n8>a?y38LspGo?ӧn;cpart of this study. All of the field measurements were automated for continuous operation using computer interface for insnd because of their potential effects on tropospheric and stratospheric ozone. This study attempts a comprehensive analysis of how recognized anthropogenic and natural influences may have affected the atmosphere since the beginning of the industrial age. Within this context, model results for past and present atmosphere are compared with available observations of  constant referencing ultraviolet absorption detector. Ancillary measurements of NO{-y} and meteorology were also made as anada, statistically evaluates these relationships through regression analysis, and yields significant results. The effect of climate was well represented by the dates of freeze-up and break-up. Year to year variability decreased with increasing latitude, with break-up being generally more variable than freeze-up in all regions. The records of six lakes show a tre controlled capillary diffusion of a laboratory synthesized PAN standard in a tridecane matrix. Ozone was measured using aGQuantitative Linksrbon concentrations over an annual cycle. The observations are analyzed to determine the dependence ofGNational Institute for Global Environmental Change (NIGEC)d to obtain a measure of the annual mean and seasonal variatio electron capture detection (GC-ECD). An improved PAN calibration method for the GC-ECD was developed based on temperature lead to a mean global warming of 2-3C. It is suggested that lake ice occurrence may be used as a first detection parameter of this warming, due to its relatively rapid integration of temperature, and the availability of freeze-up and break-up data. Two case studies are examined for the statistical relationship between ice patterns and daily temperature data. Ones, ozone (O{-3}) and peroxyacetyl nitrate (PAN) in a non-urban environment. PAN was measured using gas-chromatography with 141^1^Gomes de Azevedo,Antonio Expedito^1981^6^Atmospheric Distribution of Carbon Dioxide and Its Exchange with the Biosp here and the Oceans^Ph.D.^Columbia University^144^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^403^^^^^^^^^^^^Geochemistry^Takahashi, Taro^Takahashi, Taro^DE-AC05-84OR214000kT-WC2zdq|5|P tEϸlight. The growth pattern of plants from Quebec is characterized by a shorter life cycle; the northern plants flower consi?stently before the other populations. Plants from all three populations were grown in field plots in North Carolina and in@ Quebec. While plants from Quebec do not survive through the summer in North Carolina, those from Mississippi fail to reprAoduce in Quebec. Thus, it appears that the various populations are ecotypically differentiated. The effects of CO{-2} enriBchment on the physiology and growth of the two C{-4} grasses under study were minor. Plants respond to high CO{-2} concentCration by a slight increase in photosynthesis, in export pool size and in net assimilation rates during the first 20 days Dof growth. There was a consistent temperature by CO{-2} interaction in both chilling experiments. CO{-2} enrichment partiaElly ameliorates the deleterious effects of low temperature. The reasons for this interaction are only speculative but the Fexistence of this relationship demonstrates the danger of assessing the effects of CO{-2} enrichment by photosynthesis andG growth response to CO{-2} alone. Other environmental factors must be examined and understood. Prior studies have suggesteHd that C{-4} plants are best adapted to warm habitats and are unable to survive at higher latitudes or elevations. This stIudy demonstrates, however that _Echinochloa crus-galli_ has adapted to cool environments by ecotypic differentiation of poJpulations. It seems possible that other C{-4} grass species will also eventually spread into cooler areas by genecologicalK differentiation. Cool climate adaptations appear to involve the development of a faster phenological development and of aLn enhanced tolerance to chilling. Because of its stringent effects, chilling under high light is the most difficult challeMnge faced by C{-4} plants. With a global increase in CO{-2} concentration, the distribution of C{-4} plants is likely to eNxtend to higher latitudes and elevations because of the temperature by CO{-2} interaction and the CO{-2}-correlated global warming.أֺF Ϟo~?atas Y<"19?F׬M;὎螷tQJt~k&}_qwqzP149^1^Sasek,Thomas William^1985^6^The Implications of Atmospheric Carbon Dioxide Enrichment for the Physiological Ecology Qand Distribution of Two Introduced Woody Vines, _Pueraria lobata_ Ohwi (Kudzu) and _Lonicera japonica_ Thunb. (Japanese hoRneysuckle)^Ph.D.^Duke University^203^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^263^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AI01-81ER60012, DE-AS05-83ER60177x@6(Yzx*MlQ;/|V&B<ˣ6 GTA^262^The vine growth habit increases competitive potential for light capture. More biomass is allocated to height and leaUf area because support structures are minimized. This study considered the effects of the continuing increase in atmospherVic carbon dioxide concentration on the growth and morphology of vines. Vines were hypothesized to allocate CO{-2}-induced Wincreases in production to height and leaf area more efficiently than erect growth forms. Kudzu (_Pueraria lobata_ Ohwi) aXnd Japanese honeysuckle (_Lonicera japonica_ Thunb.) are perennial woody vines, introduced into the United States from JapYan. Both have become naturalized in the eastern US and are pernicious weeds in the Southeast capable of suppressing the naZtive flora. Kudzu and honeysuckle were grown in controlled environment chambers in the Duke University phytotron at 350, 6[75 and 1000 l l{+-l} CO{-2}, simulating double and triple current ambient CO{-2} concentration. Long-term growth at eleva\ted CO{-2} concentrations resulted in less enhancement of photosynthesis than predicted by short-term exposure. The reduct]ion of photosynthetic capacity was not due to stomatal limitations. Rather, starch accumulation in the leaves at high CO{-^2} probably reduces photosynthesis by biochemical feedback inhibition. Dry weight and leaf area were increased by CO{-2} e_nrichment especially in the young seedlings. Kudzu stems were 40% and 60% percent longer at double and triple CO{-2}, resp`ectively, than at current ambient CO{-2}. Branching was enhanced by 50% with CO{-2} enrichment. Honeysuckle stem height waas unaffected but branching was enhanced three-fold by CO{-2} enrichment. Height increase with CO{-2} enrichment was much gbreater than stem diameter increase, which is in contrast to erect growth forms. Vines maintain their favorable allocation cpatterns while still incorporating CO{-2}-induced increases in productivity. Kudzu seedling establishment, currently rare,d may be enhanced by CO{-2} enrichment due to improved growth at low irradiance and by increased water use efficiency. The egeographic range of both species may be increased due to direct effects of CO{-2} enrichment and indirect climatic effectsf due to the Greenhouse Effect. Westward spread may occur due to enhanced water use efficiency. Northward spread may occur gdue to improved growth at low temperatures with CO{-2} enrichment and due to global warming that may increase minimum winter temperatures, reducing die-back of overwintering stems.f>|cg}L}~>GqoߏcLM9?i150^1^Wray,Susan Marks^1987^6^Competitive Interactions of Two Old-Field Perennials, _Aster pilosus_ and _Andropogon virginjicus_ under CO{-2} Enrichment^Ph.D.^Duke University^167^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^265^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AS05-83ER60177, DE-FG05-87ER60575HwG wD=nR,~]}zlA^264^Differential response of species to CO{-2} enrichment may change future community structure in natural ecosystems. Imn old fields of the North Carolina Piedmont, aster (_Aster pilosus_ Willd., C{-3}) is usually the dominant perennial two ynears after abandonment. Broomsedge (_Andropogon virginicus_ L., C{-4}) outcompetes and replaces aster during the next seveoral years. When grown individually, aster responds positively to CO{-2} enrichment whereas broomsedge does not. Thus it waps hypothesized that the competitive interactions between these species would change if the atmospheric CO{-2} concentratioqn was increased. Aster and broomsedge were grown in simplified de Wit replacement series experiments in the Duke Phytotronr at 350, 500 and 650 l l{+-1} CO{-2}. The suppression of broomsedge by aster was always greater with CO{-2} enrichment sos that broomsedge grown with aster had 69% less dry weight than in monoculture at 650 l l{+-1} CO{-2}. Aster had 49% more tdry weight when grown with broomsedge than in monoculture at 650 l l{+-1} CO{-2}. Broomsedge was more drought tolerant thuan aster and under ambient conditions had a higher water use efficiency. However, under water-limited conditions, broomsedvge was not a stronger competitor than aster. With CO{-2} enrichment aster comprised 75% of total pot biomass under both wawter-limited and well-watered conditions. There could also be competition between established broomsedge and a second generxation of aster seedlings in old fields. In the Phytotron when broomsedge was grown for six weeks before aster emerged, astyer seedlings did not suppress the growth of broomsedge even with CO{-2} enrichment. These studies have shown that competitzive interactions between these old-field perennials change under CO{-2} enrichment when grown in a controlled environment.{ Future increases in atmospheric CO{-2} concentration may slow the rate of succession in old fields under both drought and| non-drought conditions. However, aster will not necessarily eliminate broomsedge from the perennial herbaceous community }as broomsedge ultimately will reach a size where competition with aster seedlings does not delay its growth. It is hoped t~hat these studies will contribute to the understanding of the dynamics of community structure in the face of environmental change.j)PM lSf5٨@6j)PM lSf5٨@6j)PM lSf5٨@6j)PM lSf5٨151^1^Luo,YaoHua^1989^6^Responses of Well-Watered and Water-Stressed _Abutilon theophrasti_ (C3) and _Amaranthus hybridus_ (C4) to Long-Term Differences to CO{-2} and Humidity^Ph.D.^Duke University^192^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^267^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AS05-83ER60177, DE-FG05-87ER60575Sf5٨@6j)A^266^Two dicotyledonous annuals, _Abutilon theophrasti_ Medik. (C3) and _Amaranthus hybridus_ L. (C4) were used to examine responses to differences in soil water (well-watered and slowly water-stressed for 20 days), atmospheric humidity (45% and 85% RH at 30 C), and CO{-2} (350 and 650 l/l) in terms of water relations, gas exchange, and biomass production. A subirrigating system was used in growth chambers with 1000 mol photons m{+-2} s{+-1} 14 h/30 C days and 10 h/24 C nights. Water deficit was gradually induced in vermiculite by decreasing the osmotic potential with increasing concentrations of polyethylene glycol (20,000 MW) in the subirrigating system. This allowed lowering relative humidity without directly inducing or aggravating soil water stress and provided conditions similar in time course to dry-down experienced in the field. Under the same light and temperature conditions as growth, photosynthetic rate for the C3 species (_Abutilon theophrasti_) tended to saturate after 650 l CO{-2}/l, whereas the C4 species (_Amaranthus hybridus_) reached the maximum rate before 350 l CO{-2}/l. As a result, CO{-2} enrichment stimulated the C3 plant in biomass production but not the C4 species. Elevated leaf water potential due to a reduction in transpiration under CO{-2} enrichment alleviated the depression of low humidity on leaf expansion in both species. However, it did not prevent the depressive effect of the low humidity-induced decrease in photosynthesis in the C3 plant, so biomass production for the 32-day growth cycle was the highest in plants grown in CO{-2} enrichment and humid air. The dry air C3 plants had a higher leaf water content but lower biomass per plant than did the humid air plants and the C4 plant had a similar tendency. It indicates that absolute water content has relatively little influence on whole biomass production by the plant. After water stress, both species maintained their photosynthetic rates until leaf water potential declined to -1.1 to -1.5 MPa. At later water stress, however, water potential declined more rapidly in the dry air plants than in the humid air plants yet their photosynthetic rates were similar. Assimilation versus internal CO{-2} concentration curves showed that the stomatal limitation of assimilation was dominant during early water stress while non-stomatal limitation of assimilation mainly occurred later in water stress. Correspondingly, the ratio of intercellular CO{-2} to ambient CO{-2} concentration (Ci/Ca) decreased during early stress but increased later in water stress. Therefore, Ci/Ca may be used as an indicator of stomatal or non-stomatal limitation of assimilation for water-stressed plants. pp?~?p152^1^Reid,Chantal Danielle^1990^6^The Carbon Balance of Shade-Tolerant Seedlings of _Fagus grandifolia_ and _Acer saccharum_ under Low Irradiance and CO{-2} Enrichment^Ph.D.^Duke University^180^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^269^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AS05-83ER60177, DE-FG05-87ER60575^8p8A^268^The photosynthetic response to irradiance of beech (_Fagus grandifolia_) and sugar maple (_Acer saccharum_) was compared on seedlings grown at current and elevated atmospheric CO{-2} to determine the effects of CO{-2} enrichment on leaf carbon exchange. In both species, maximum photosynthesis was significantly increased with CO{-2} enrichment but leaf dark respiration was not significantly changed. Photosynthesis of beech was consistently lower than that of sugar maple while both species had similar leaf respiration rates. Beech experienced greater enhancement of growth with CO{-2} enrichment suggesting that photosynthetic capacity was not a good indicator of the net effect of CO{-2} enrichment. Whole-plant carbon balances were compared for seedlings grown under low irradiances and two atmospheric CO{-2} to determine if shade-tolerant seedlings of these two species have similar patterns of carbon exchange rates, and how carbon exchange dynamics are affected by CO{-2} enrichment. Under current CO{-2}, whole-seedlings of beech had lower carbon uptake during the daytime while carbon loss to root respiration and nighttime leaf dark respiration was similar for both species. A lower net carbon gain for beech resulted under current CO{-2}. Under elevated CO{-2}, both species showed similar whole-seedling carbon uptake, indicating a significant increase in CER with CO{-2} enrichment for beech. Total carbon loss to leaf respiration was decreased for beech only and carbon loss to root respiration was not changed by CO{-2} enrichment for either species. A greater net daily C gain for beech indicated an improvement of growth with CO{-2} enrichment relative to sugar maple. The carbon balances of beech and sugar maple suggest 2 types of carbon allocation contributing to growth and survival in low light: 1) a low carbon uptake coupled with low root respiration rate for slow growth (beech); and 2) a high carbon uptake with low root respiration cost allowing slow growth (sugar maple). CO{-2} enrichment enhances the first type by increasing photosynthesis and reducing respiration cost, and thus favoring growth of beech. This study suggests a potential change in species distribution in CO{-2} enriched atmospheres because of species specific responses such as a greater enhancement of beech versus sugar maple.8pq8pp8p8p*b216W8  153^1^Dippery,Joy Kirsten^1993^6^Effects of Reduced and Elevated CO{-2} Partial Pressure on C3 and C4 Plant Growth^M.S.^Duke University^52^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^271^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-FG05-87ER60575p p88 8 8pq8pA^270^In order to study C{-3} and C{-4} plant growth in atmospheric CO{-2} levels ranging from Pleistocene through predicted future levels, _Abutilon theophrasti_ (C{-3}) and _Amaranthus retroflexus_ (C{-4}) were grown in growth chambers controlled at CO{-2} partial pressures of 15 Pa (approximate Pleistocene minimum), 27 Pa (preindustrial), 35 Pa (present) and 70 Pa (elevated). After 35 days of growth, CO{-2} had no effect on the relative growth rate, total biomass or partitioning of biomass in the C{-4} species. However, the C{-3} species showed increasing biomass with rising CO{-2} partial pressure. C{-3} plants grown in 15 Pa CO{-2} had only 8% of the total biomass of plants grown in 35 Pa CO{-2}. In 15 Pa CO{-2}, C{-3} plants had lower relative growth rates, lower specific leaf weights and stunted reproduction relative to plants grown in higher CO{-2} partial pressures. C{-3} plants grown in 70 Pa CO{-2} showed relatively greater partitioning of biomass to roots compared with plants grown in 15 Pa CO{-2}. This study suggests that 1) C{-3} species may acquire a competitive advantage over C{-4} species with increasing atmospheric CO{-2} partial pressure; 2) C{-4} species may have had a competitive advantage over C{-3} species in the past when atmospheric CO{-2} partial pressure was substantially lower than current levels; 3) and supports the hypothesis that low CO{-2} partial pressures of the past may have been an important factor favoring the evolution of C{-4} species.5W8x88*b45W> ~x8154^1^Griffin,Kevin Lee^1994^6^Effects of Resource Availability on Carbon Utilization in _Pinus taeda_ L. and _Pinus ponderosa_ Dougl. ex Laws. Seedlings^Ph.D.^Duke University^169^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^273^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AS05-83ER60177, DE-FG05-87ER60575 LaserJet Series IIHPLASEIA^272^The growth and development of tree seedlings is often regulated by the availability of resources such as atmospheric CO{-2} and soil nitrogen. Our ability to predict the effects of resource availability on plant growth is limited by our poor understanding of the control of carbon flow during plant growth and development. Traditionally, biomass has been used to describe carbon and energy allocation; yet, the reduction state of carbon in this biomass may be more informative. I analyzed data from the primary literature to characterize the range, mean and amount of variation in construction cost; the amount of glucose required to provide carbon skeletons, reductant and ATP for biosynthesis. Resources that are actively taken up (i.e. nitrogen) require the construction and maintenance of expensive biochemical machinery, increasing construction cost. Carbon uptake requires energetically expensive machinery but can lead to the formation of inexpensive carbohydrates, diluting construction cost. I manipulated CO{-2} and nitrogen resource availability in a phytotron to examine the nature of carbon and nitrogen interactions in loblolly and ponderosa pine seedlings. Oxygen bomb calorimetry was used to determine construction cost. The relationships between resource availability and construction cost were mechanistically analyzed by comparing cost with photosynthesis, respiration, leaf carbon-, nitrogen, soluble sugar-, starch-, and total nonstructural carbohydrate-concentration, leaf mass, specific leaf mass, total plant mass and carbon allocation. A sensitivity analysis of the response of construction cost to changes in the biochemical fractionation of pine leaves was performed with a simple model and supported the empirical results. Over a wide range of carbon and nitrogen availabilities small differences were found in leaf construction costs. Elevated CO{-2} decreased, and elevated N increased leaf construction cost (g glucose g{+-1}). Carbon and nitrogen resources were interactive, reflecting whole plant source-sink relationships. CO{-2} effects on construction cost were correlated with increased nonstructural carbohydrates, and N effects were correlated with leaf N (protein). The response of leaf construction cost is consistent with our understanding of basic plant response to resource availability, yet the absolute differences observed were small, suggesting that carbon partitioning and allocation are controlling plant energy dynamics.Right-Aligned Paragraph Numbers _o` ` 155^1^Lewis,James D^1994^6^Effects of Mycorrhizae and Phosphorus Supply on Response of _Pinus taeda_ L. Seedlings to Elevated CO{-2}^Ph.D.^Duke University^157^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^275^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AS05-83ER60177, DE-FG05-87ER60575x+Da7Right ParRight-Aligned Paragraph NumA^274^Mycorrhizal fungi play a critical role in nutrient uptake by most tree species, and the importance of this function in regulating the outcome of increasing atmospheric CO{-2} on natural ecosystems is widely assumed. However, few studies have considered whether the presence or absence of mycorrhizae differentially affects the response of nutrient-limited host trees to elevated CO{-2}. Understanding the integration of leaf-level, root-level, and whole-plant processes is crucial to predicting the influence of mycorrhizal fungi on the response of host trees to elevated CO{-2} across a range of environments. I manipulated mycorrhizal status and phosphorus supply in a phytotron to investigate the role of the mycorrhizal fungus _Pisolithus tinctorius_ (D. Marx isolate #306) in the response of loblolly pine seedlings to elevated CO{-2} under different phosphorus regimes. Monthly measurements of biomass accumulation and allocation, relative growth rates and needle characteristics were used to examine whole-plant responses. Effects on root-level processes were examined by comparing root nutrient and carbohydrate concentrations with the extent of mycorrhizal colonization. Photosynthesis and non-destructive measurements of rubisco activity and ribulose 1,5-bisphosphate regeneration capacity were used to examine effects on leaf-level processes. Linkages among photosynthetic processes were examined using covariate analysis and used to infer photosynthetic regulation by the rate of carbohydrate utilization. Mycorrhizal colonization significantly increased phosphorus uptake and growth of phosphorus-limited seedlings, but did not affect the response of seedling photosynthesis or biomass to elevated CO{-2}. In fact, phosphorus-limited seedlings showed the greatest relative responses to elevated CO{-2}, apparently as a result of increased phosphorus uptake and increased phosphorus use efficiency. Additionally, elevated CO{-2} did not differentially affect seedlings grown from seeds obtained from Florida and coastal North Carolina populations. However, elevated CO{-2} reduced photosynthetic capacity and tissue phosphorus concentrations in seedlings supplied with phosphorus at levels adequate for maximum seedling growth in ambient CO{-2}. These results suggest that phosphorus-limited loblolly pine seedlings initially will respond to elevated CO{-2} due to increases in phosphorus uptake and phosphorus use efficiency, but ultimately phosphorus-limitation will reduce or eliminate the fertilization effect of elevated CO{-2}.X stable for horizontally uniform basic states with a vertical gradient in the basic state absorber mixing ratio. Two types of instability are identified, described as the advective mode and the propagating mode. The advective mode is usually unstable when the basic state absorber mixing ratio decreases with height. Upward motion, high absorber concentration and warm temperatures are typically in phase for this mode. Growth rates, which can be competitive with those associated with baroclinic instability, are largest for perturbations that are much shorter than the internal deformation radius. Thus, the requirement that the basic state be horizontally uniform is often satisfied for the advective mode. The propagating mode is normally unstable when the basic state absorber mixing ratio increases with altitude. Propagating waves such as Rossby and inertia-gravity waves are amplified by the feedback with absorber transport and radiative heating. Growth rates for the propagating mode are usually bounded by the frequency of oscillation of the ambient wave, an important limitation for slowly propagating waves such as Rossby waves. Vertical transport of the absorber by the amplifying mode is down the basic state absorber gradient in each case. Complicating factors such as the effects of dissipative processes, vertical shear, and scattering of sunlight are also considered. The competition between vertical transport of absorber due to the modal instability mechanism described above and that due to initial horizontal patchiness of an absorber injection is also examined. For patches with horizontal scales much larger than the deformation radius the modal form of absorber transport is shown to be important, while for smaller patch scales the nonmodal form dominates.ms; greenhousegas emissions from industry and Cracken, Michael C.^W-7405-ENG-48gional climate; response of vegetation to elevated carbon dioxide; treering data; and dA^278^This study examines the effects that increased emissions of anthropogenic and naturally-occurring trace gases have on the chemical and physical processes in the global atmosphere. The Lawrence Livermore National Laboratory (LLNL) one- and two-dimensional chemical-radiative-transport models of the troposphere and stratosphere, are used to calculate the net effects that variations in these trace gases, either individually, or taken together have on the ozone distribution and temperature structure. Using the LLNL one-dimensional model, calculations are made that include large changes of NO{-x}, Cl{-x}, and HO{-x}. The object was to see if any interesting or unexpected effects could be found. The nitrous oxide boundary value is varied from to 8 times the reference (1960) value of 300 ppb. Stratospheric Cl{-x} is varied from 0 to 22 ppbv. Special atmospheres are considered in which all HO{-x}, NO{-x}, and Cl{-x}, or combinations of these are omitted from the  reference atmosphere. A sensitivity study is carried out using the LLNL one- and two-dimensional chemical-radiative-transp ort models to examine possible effects of future aircraft NO{-x} emissions on stratospheric ozone. A broad range in magnit ude, altitude, and latitude of the assumed NO{-x} emissions is examined for various background Cl{-x} values. The change i n column-ozone is calculated for each sensitivity scenario relative to a reference atmosphere. Comparisons between the one - and two-dimensional models are discussed. The effect on the ozone-column due to variations in the eddy diffusion representation (K{-yy} and K{-zz}) is shown for one aircraft scenario. The emissions and atmospheric concentrations of several trace gases (N{-2}O, CH{-4}, CO{-2}, CFCl{-3}, CF{-2}Cl{-2}, CCl{-4}, and CH{-3}CCl{-3}), plus the effect of both the 11 year solar sunspot cycle and NO{-x} produced from the nuclear test series of the late 1950's and early 1960's are examined using the LLNL two-dimensional model. Changes in ozone-column, local ozone, temperature profiles, and various other species distributions are compared to observations made from the ground, balloons, aircraft, rockets, and satellites. By modeling the emissions of these trace gases on the chemical and physical processes in the global atmosphere, the potential accuracy of the two-dimensional model can be estimated and the prospects of future perturbations can be more realistically assessed. The effect of the eddy diffusion representation (K{-yy} and K{-zz}) on the two-dimensional transport of trace constituents is investigated, using analyzed carbon-14 and strontium-90 data from the nuclear test series in the late 1950's and early 1960's. Here various K{-yy} and K{-zz} values, as a function of latitude and altitude, were used to see what values best represented or corresponded with short and long term transport of the above two tracers. In addition, the model was used to help verify which of the two available estimates for bomb stabilization cloud height, Seitz [1968] or Peterson [1970]. better represents the available data. The effect of varying the eddy transport is examined in terms of model-calculated change in O{-3} column distributions. The best eddy diffusion representation derived from the tracer study gave the best ozone-column distribution relative to observational data.]R($UO:V]H;W8@J2!T M:&4@1F%Ud part of this research (Chapter 3) studies the influence of zonally varying flows on energy propagation of tropically for?ced waves. A 9-year (1980-1988) averaged 300 mb January basic flow is examined, which exhibits strong zonally varying jet @streams in the Northern Hemisphere, and a nearly zonally uniform flow in the Southern Hemisphere. A two-dimensional WKB anAalysis shows that the group velocity depends on the sum of three terms: 1) the basic state wind vector; 2) a vector that iBs parallel to the absolute vorticity contours; and 3) the local wavevector. As the forcing frequency decreases, the ray paCths approach the direction of the local wavevector. Generally, the changes of wave amplitude along ray paths are determineDd by the meridional variations of horizontal wave scales. However, the zonal variation of horizontal wave scale can still Eplay an important role at the jet exit regions. A global energetics analysis demonstrates that the energy conversion from Fthe basic flow becomes more important as forcing frequency decreases. A local energetics analysis shows that for long periGod (> 30 days) forced disturbances, the energy redistribution terms, i.e., the advection and the pressure work terms, are Halso significant along the extratropical jet streams in the Northern Hemisphere. Hence, long period disturbances are stronIgly influenced by the jet streams in the Northern Hemisphere, and are much less sensitive to the position of the tropical Jforcing than those of intermediate period (< 30 days). Consistent with observations, long (intermediate) period disturbances dominate in the Northern (Southern) Hemisphere, where the basic flow is more (less) zonally varying.LA^284^The momentum equations that describe laminar or turbulent flow are the Navier-Stokes equations. When these equationsM are time averaged, by a method outlined by O. Reynolds, new terms called Reynolds stresses appear in these equations. TheNre are several ways to represent these Reynolds stresses, and the manner in which these terms are determined is called a tOurbulence model. In this research the standard K- and Rodi's algebraic stress models were used to calculate one-dimensionPal fully-developed turbulent channel flow, turbulent two-dimensional flow over a backward facing step, and turbulent two-dQimensional flow around a rectangular cylinder. For fully developed channel flow the K- model predicts equal normal ReynolRds stresses, which has not been observed in laboratory measurements. The algebraic stress model (ASM) correctly separates Sthese normal stresses, which is a necessary condition for generating the secondary currents which are known to exist in reTctangular duct flows. The K- model for flow over a backward facing step predicts velocity distributions and separation leUngths which are very good when they are compared with the experimental results. However, the normal Reynolds stresses wereV nearly identical, which has not been observed in laboratory studies. Results from Rodi's ASM for this test problem show aW distribution of the normal Reynolds stresses that are separated and generally match the experimental data very well, espeXcially near the step. The K- model for turbulent flow around a rectangular cylinder predicted vortex shedding at a lower Yfrequency than was measured experimentally. Rodi's ASM produced more energy in the mean flow, and the vortex shedding freqZuency was almost identical to laboratory results. In conclusion, Rodi's ASM separated the normal Reynolds stresses and put more energy into the mean flow and is therefore considered to be a better turbulence model than the standard K- model.\ depletion, is increasing at an annual rate of about 0.25%/yr. By use of a global model of the changing terrestrial nitrog]en cycle, the timing and magnitude of this increase are shown to be consistent with enhanced microbial N{-2}O production d^ue to fertilizer, land clearing, livestock manure, and human sewage. Fertilizer appears to be a particularly important sou_rce. Increasing emissions from additional anthropogenic N{-2}O sources, including fossil fuel combustion and nylon product`ion are also shown to coincide with and contribute to N{-2}O's annual atmospheric increase. Collectively, these industriala, combustion-related, and enhanced microbial N{-2}O emissions add up to a total anthropogenic source of about 5 Tg N/yr. Nbatural N{-2}O emissions from microbial activity in soils and oceans and from natural fires are estimated to produce an anncual source of about 11 Tg N/yr, of which the oceans contribute a substantially larger fraction than reported in most currednt budgets. In contrast to anthropogenic emissions, which are increasing rapidly, natural emissions are predicted to remaien relatively constant from 1860 to 2050, although this prediction ignores possible enhancements in microbial N{-2}O producftion due to global warming. Also in contrast to anthropogenic emissions, which are heavily dominated by the northern hemisgphere, the natural source is fairly evenly distributed over the Earth. The predicted magnitude of the natural source is chhecked against an estimate of the N{-2}O stratospheric sink, while the predicted present day distribution of natural and anithropogenic sources is tested in a 3-dimensional transport model run. This run reproduces the observed 1 ppb interhemisphejric gradient (higher in the north), and suggests that larger gradients may exist over strong continental source regions. Skubstantial increases in most anthropogenic N{-2}O sources are projected for the future if current trends continue. In contlrast to purely industrial greenhouse gases like the CFCs, which can be phased out fairly easily, attempts to control N{-2}mO emissions may conflict with efforts to reduce urban smog (i.e., NO{-x} emissions) and to feed the world's growing human npopulation. These conflicts could be mitigated, however, by improved energy efficiency, decreased dependence on synthetic fertilizer, reduced numbers of livestock, and a slowdown in the rate of human population growth.8pp162^1^Meehl,Gerald Allen^1987^6^Interactions Between the Asian Monsoons, the Tropical Pacific, and the Southern Hemisphereq Extratropics^Ph.D.^University of Colorado^160^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^289^^^^^^^^^^^^Geography^Barry, Roger G.^Washington, Warren M.^DE-AI01-80EV10220p8p8pp8p 8p?8psA^288^Relatively strong and weak years of Indian monsoon rainfall are selected and used as a starting point to follow the tevolution of the annual cycle of precipitation in the tropical Indian and Pacific sectors. Analysis of observations shows uthat the dynamically coupled ocean-atmosphere system in the Indian-Pacific region produces Southern Oscillation-type signavls in atmosphere an ocean in many years, with extremes being manifested as Warm and Cold Events. Four different GCM simulawtions are analyzed. One is run with the specified annual cycle of observed sea surface temperatures (SPEC SST), and two arxe coupled to a simple 50 m deep slab ocean model with present (1 x CO{-2}) and doubled (2 x CO{-2}) amounts of atmosphericy carbon dioxide. The 50 m slab ocean model acts as a simple heat reservoir with no provision for currents or upwelling. Duze to these inherent limitations, the SPEC SST simulation most closely represents observed mean conditions, while the 1 x C{O{-2} and 2 x CO{-2} integrations produce a progressively more Warm Event type of response in the tropics. The high southe|rn latitudes in these mode runs show internally consistent circulation anomalies in the 2 x CO{-2} compared with the 1 x C}O{-2} and SPEC SST. This involves a sensitivity to the annual cycle of SSTs at midlatitudes and sea ice extent at high lat~itudes, both of which have an effect on the semiannual oscillation at those latitudes. A fourth GCM experiment with an altered convective scheme but with SSTs and sea ice held constant produces a warmer tropical troposphere, an intensified equator-to-pole temperature gradient, and a deepened circumpolar trough year round. However, the observations show a seasonal evolution of anomalies in the Southern Hemisphere such that the circumpolar trough is deeper during southern winter the year of a Warm Event and shallower the following summer. The observed sequence of Warm minus Cold Event composites shows a poleward migration of anomalies with the tropics leading the high latitudes by about half a year. This poleward migration is most evident in the Pacific, and appears to be related to the annual cycle of the entire coupled ocean-atmosphere system in the Indian and Pacific sectors.c}ܣco͠||}|}}ߧ =r||>ߋoC163^1^LaFontaine,Carolyn Vada^1988^6^Comparison of the Simulated Climate and Geologic Observations from Equatorial Land Regions for the Past 18,000 Years^M.S.^University of Wisconsin - Madison^62^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^291^^^^^^^^^^^^Meteorology^Kutzbach, John E.^Kutzbach, John E.^DE-FG02-85ER6034999> 8yIJr7#N?w9C9EoCA^290^Equatorial land results of paleoclimate simulations by Kutzbach and Guetter (1986) were examined for three areas: New Guinea/northern Australia, eastern equatorial Africa and western equatorial South America. Area-averaged results were computed at 3000 year intervals for the past 18,000 years. Results were compared with geologic data and the results of similar paleoclimatic experiments. Prescribed changes in orbital parameters (Milankovitch mechanism) had the greatest effects on the model results at 9 and 6 kyr BP but at 18 and 15 kyr BP prescribed boundary conditions were more important in the results. Modeled results were compared with geologic data compiled from many sources. Much colder temperatures and drier conditions were shown by the geologic data at 18 and 15 kyr BP than are simulated by the model. However, at 9 kyr BP the agreement was better. Although the magnitude of the simulated changes did not agree with the geologic inferences, the trend of those changes agreed reasonably well with geologic data in each region. Results from the Kutzbach and Guetter climate simulation were also compared with similar climate simulations. The most direct comparison was with that of Rind and Peteet (1985). While the simulated surface temperature in each of the three regions was similar, precipitation results were more variable.88 8Á*b209W8pxp8 p8p ~88p164^1^Meyer,Mary Kathryn^1988^6^New Primary Productivity Estimates for the Last 18,000 Years Evaluated from Simulations by a Global Climate Model^M.S.^University of Wisconsin - Madison^39^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^293^^^^^^^^^^^^Meteorology^Kutzbach, John E.^Kutzbach, John E.^DE-FG02-85ER60348 p8Á*b209W8pA^292^Net primary productivity (NPP) is estimated over land for the past 18,000 years using a simple model developed by Lieth (1973) and annual temperature as simulated by a climate model (Kutzbach and Guetter, 1986). Modern values of NPP are determined and summarized by area-average and by estimates in Walter's vegetation zones (1973). The modern evaluation serves as measure for studying past values of NPP. For the globe, the area-averaged value of modern NPP is about 995 g/m{+2}/year. Sensitivity experiments performed by globally altering the modern temperature or precipitation illustrate that precipitation changes are most likely to affect equatorial and subtropical NPP values while both temperature and precipitation changes affect midlatitude NPP values and mainly temperature changes affect high latitude NPP values. The simulations of past climates lead to NPP estimates at 18 kyr BP about 30% lower than modern over the northern hemisphere, due to the presence of the ice sheet. from 12 to 6 kyr BP the NPP values, as compared to modern, were about 15% greater over the northern tropics and about 10-15% less over the southern tropics because northern summer monsoons were more intense and southern summer monsoons were weaker at this time (Kutzbach and Guetter, 1986).p8pp88 8165^1^Hu,Jianhong^1994^6^Uptake of a Series of Gas-Phase Halogenated-Acetic Acids and Halogen Molecules by Aqueous Droplet Surfaces^Ph.D.^Boston College^180^Dissertation^^^Atmospheric Sciences^^^^^^^295^^^^^^^^^^^^Chemistry^Davidovits, Paul^Davidovits, Paul^DE-FG02-91ER61208p8pp888~p8pA^294^The importance of gas-liquid heterogeneous chemistry in the atmosphere has been recognized. It has been found that heterogeneous reactions could dramatically alter the chemical composition of the atmosphere. Here we examine the heterogeneous chemistry of two atmospheric systems using a well developed droplet apparatus. This method combines a monodisperse droplet stream with a low pressure flow reactor. The uptake of gas by the droplets is determined by measuring changes in gas phase density using a mass spectrometer as the droplet area is changed. Gas-liquid uptake studies have been performed for the following series of halo-acetic acids (as well as acetic acid itself): CF{-3}COOH, CCl{-3}COOH, CClH{-2}COOH, CCl{-2}HCOOH, CF{-2}ClCOOH, and CH{-3}COOH. These species (expect CH{-3}COOH) are the final degradation products of alternative chlorofluorocarbons. The mass accommodation coefficients for these species have been determined. Results indicate that the mass transfer of these halo-acids to atmospheric cloud droplets are not limited by mass accommodation. The studies of the uptake of gas phase Cl{-2} and Br{-2} by aqueous surfaces as a function of Br{+-} and I{+-} ion concentration have also been completed. Since the solubility of the halogen molecules X{-2} (X = Cl or Br) is low, the measured uptake is primarily due to the aqueous reaction of the species with the halide ion Y{+-} (Y = Br or I) via X{-2} + Y{+-} ---> XY + Y{+-}. The magnitude of the measured uptake and its functional dependence on the ion concentration are not in accord with simple bulk phase reaction of the species. The data indicate that reactions at the gas-liquid interface play a significant role in the gas uptake process. The atmospheric implications of the results have been examined.*b26W8p?166^1^Zaff,David Z^1994^6^A Dynamical Explanation for Longitude Dependent Ozone and Temperature Trends in the Northern Hemisphere Winter^M.S.^University of Arizona^21^Thesis^^^Atmospheric Sciences^^^^^^^297^^^^^^^^^^^^Atmospheric Sciences^Hood, Lon L.^Hood, Lon L.^DE-FG03-93ER61727^*b26W8xp*b26W>xp*b8W>x*b8WA^296^Ozone and temperature data are obtained from the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus 7 satellite and Channel 4 of the Microwave Sounding Unit (MSU) on the NOAA operational satellites. January averages are analyzed separately via a multiple regression statistical model with dependences on a linear trend, the quasibiennial oscillation (QBO), and the solar cycle. Trends show that both data sets exhibit significant negative trends at middle to sub-polar latitudes occurring over Russia and the western Pacific, with smaller negative trends at mid-latitudes occurring over the eastern United States. Positive trends occur in the sub-polar latitudes over the Atlantic, although neither ozone nor temperature trends in this region are found to be statistically significant. The strongest negative trends are located in the same geographic area where climatological ozone and temperature are a maximum. A calculation of three year January ozone and temperature averages for 1980-82 and 1989-91 yields differences that are similar to the statistically derived ozone and temperature trends. These composite plots show a significant decrease in the wave 1 amplitude of both ozone and temperature, in agreement with the trends. A steady state ozone perturbation model under adiabatic and geostrophic conditions is applied to test whether changes in dynamics alone, represented by the geopotential height fields, can explain the observed longitude distribution of ozone trends. Similarly, the hydrostatic equation is used to study the longitude distribution of temperature. Results show that changes in the stationary wave pattern alone can explain the observed longitude dependence.<|}oteorology^Baer, Ferdinand^Baer, Ferdinand^DE-FG05-91ER61219 Temperature Trends in the Lower Stratosphere: Latitude and SeA^218^Regional differences of climatic change are of importance in the study of climate history and in climate forecasting. In this research, long-term precipitation records and temperature records of western Europe and East Asia have been tested for homogeneity and analyzed for evidence of trend, periodicity, and disturbance on seasonal and annual basis using time series techniques. Polynomial regression analysis on this data set indicated that precipitation and temperature had been increased in the past 100 years in both areas. Power spectrum analysis showed some statistically significant high frequency fluctuations. One with 2 to 2.5 year period was most widespread in regions and in seasonal series. A comparison of the dates of the great volcanic eruptions and the climatic data suggested great volcanic eruptions could cause precipitation increase or decrease and temperature decrease. In conclusion, it can be stated that the general terms of climatic changes were of the same nature on a continental scale in recent historical time.ferences are found. An independent analysis reporA^172^A statistical analysis of seasonal precipitation from reporting stations over Northern Hemisphere land areas and five major wheat-producing regions covering the interval 1851-1980 is performed. The regions defined were as follows: Soviet West, Soviet East, Upper USA, Lower USA, and China. Monthly precipitation totals are initially converted to probabilities of the gamma distribution after which these values are interpolated to an equidistant grid with an exponential weighting f168^1^Liao,Liang^1993^6^Ka-Band Radar Research Applications for Ice and Water Clouds^Ph.D.^University of Utah^220^Dissertation^^^Atmospheric Radiation Measurement (ARM)^^^^^^^301^^^^^^^^^^^^Meteorology^Sassen, Kenneth^Sassen, Kenneth^DE-FG02-ER61055A^300^To obtain scattering properties of nonspherical cloud particles, a description of the electric field integral equation and its solution procedure using the CG-FFT numerical scheme is given. The validity and accuracy of the CG-FFT results have been checked by comparing them with the Mie theory and experimental measurements. The range of the particle dimensions valid for the Rayleigh approximation is also determined. Scattering and polarization characteristics of ice particles with typical habits found in ice clouds are analyzed at Ka-band wavelength. The relationships between Ka-band equivalent radar reflectivity factor Z{-e} (mm{+6}/m{+3}) and cirrus ice content and ice crystal precipitation content IWC (mg/m{+3}) are developed through regression analysis on the results of the computed Z{-e} and IWC from measured ice particle size distributions. It is concluded that the Z{-e}-IWC relationships depend only slightly on the polarization state and zenith angle of the radar beam as a result of oriented particle scattering effects. For vertically pointing operations, we find IWC = 7.49Z{-e}{+0.78} for aircraft-measured cirrus cloud compositions, and IWC = 21.8Z{-e}{+0.79} for precipitating ice crystals measured in polar regions. In addition, comparisons between the Ka-band radar and lidar measurements for cirrus clouds are made using data collected from 17 July-30 November 1990. Our findings reveal that the cloud-center altitude, cloud thickness and ice water content vary from 7 to 10 km, 1.6 to 5.5 km and 0.5 to 30 mg/m{+3}, respectively. The maximum ice water path from our observations is 38 g/m{+2}. The two-way lidar attenuation coefficient A (dB/km) at the ruby wavelength, while traversing in cirrus clouds, is estimated from the derived equation A = 3.40Z{-e}{+0.79} by the simultaneous Ka-band radar measurements, and the lidar range-averaged backscatter-to-extinction ratio is derived from the lidar equation and determined from both the Ka-band radar and the lidar data. The numerical simulations of the Ka-band radar signal in the water phase clouds have been performed in terms of the meteorological parameters from a one-dimensional adiabatic cloud model. The regression equations linking the radar reflectivity factor Z to liquid water content LWC (g/m{+3}) and median volume diameter D{-0} (m) are calculated from the results of simulations from an adiabatic cloud model, yielding Z = (3.6/N{-d})LWC{+1.8} and Z = (2.07 x 10{+-12}N{-d} - 1.37 x 10{+-11})D{-0}{+5.83} respectively, where N{-d} is the concentration of cloud droplets. Comparison with empirically-based relationships for cumulus and stratocumulus clouds shows the best agreement for N{-d} of about 100 cm{+-3}.?cies^Ph.D.^Boston College^175^Dissertation^^^Atmospheric Sciences^^^^^^^303^^^^^^^^^^^^Chemistry^Davidovits, Paul^Davidovits, Paul^DE-FG02-91ER61208A^302^Heterogeneous reaction pathways involving aqueous droplets in clouds and fogs have been recognized as major mechanisms for the chemical transformation of atmospheric trace gases. Here we examine the heterogeneous chemistry of two atmospheric systems using a previously developed fast droplet experiment and a new bubble column apparatus. Gas-liquid uptake studies have been completed for the following series of carbonyl and haloacetyl halides: CF{-3}CFO, CF{-2}O, CF{-3}CClO, CCl{-2}O and CCl{-3}CClO. Some of these species have been shown to be degradation products of hydrochlorofluorocarbons and hydrofluorocarbons which have been proposed as substitutes for ozone depleting chlorofluorocarbons. The experiments yielded values for the product of the Henry's law coefficient (H) and the liquid phase hydrolysis rate constant (k) in the form Hk{+-}. Results indicate that the tropospheric removal of the degradation products is fast enough not to contribute to the ozone depletion potential of their parent species. A series of aqueous phase uptake studies have also been completed for key biogenic sulfur species in the marine boundary layer. Reduced sulfur species of biogenic origin CH{-3}SCH{-3}, H{-2}S, CS{-2}, CH{-3}SH and OCS are a major source of sulfur in the marine atmosphere. These species and their oxidation products CH{-3}SO{-3}H (MSA), (CH{-3}){-2}SO (DMSO), and (CH{-3}){-2}SO{-2} (DMSO{-2}) dominate the production of aerosol and cloud condensation nuclei in the clean marine atmosphere. Henry's law coefficients and Sctchenow saltout coefficients have been obtained for the reduced sulfur species and mass accommodation coefficients have been obtained for the oxidized sulfur species. The atmospheric implications of the results have been examined. The species DMSO, DMSO{-2} and MSA which exhibit relatively large uptake were studied with the fast droplet apparatus previously described in detail. The other species studies in this work exhibited uptakes too small to be measured with the droplet apparatus. A new more sensitive bubble column apparatus was developed for the study of these molecules. In the bubble column apparatus, a low pressure gas flow, carrying trace gas diluted in helium carrier gas, is bubbled through a liquid. The bubbles and their transit through the liquid are carefully characterized. Measurements of gas depletion yield the desired characteristics.stics.iߌ~;G|o-layer AGCM was synchronously-coupled with a six-layer ocean model), and the GISS nine-layer AGCM (in years 26-35 of a 35-year control integration with prescribed oceanic heat transport and mixed-layer depth). Model validation is performed in a North America/Atlantic/European study area. Prior to statistical significance testing, the principal seasonal characteristics of the observed Azores High (AH) and Iceland Low (IL) are analysed with the aid of time-averaged MSLP maps and objective locational and intensity indices. Dynamical explanations are proposed for the most important AH/IL seasonal cycle cha racteristics. These results are then used to test the performance of the three models in simulating center of action (COA) seasonal cycle characteristics. All three GCMs have large, systematic errors throughout the seasonal cycle in their simul ation of AH/IL position and intensity, and all generate an unrealistic 'Greenland High'. The main focus of the investigati on is on the statistical aspects of control run validation. Eighteen different statistics are used to test the significanc e of differences between observed and simulated means, variances and spatial patterns. Principal components analysis (PCA) and correlation analysis are applied in order to identify statistics which provide equivalent, overlapping or unique information. test statistic significance is determined using Preisendorfer and Barnett's permutation procedures, which provide a means of circumventing statistical problems commonly encountered in significance testing - notably multiplicity, spatial autocorrelation, unknown reference distributions and small time samples of model data. Statistics which measure the degree of spatial autocorrelation in latitudinal and longitudinal directions (and at different spatial lags) are also used to compare observed and simulated fields. Validation of the simulated seasonal cycles of MSLP (using observed data for the decade 1971-80) indicates that all three models have statistically significant errors in the mean field, variances and spatial patterns. For the three models examined here, test statistic significance levels for observed/simulated differences in the mean field and spatial patterns are relatively insensitive to decadal time-scale variability in the observed MSLP data. Significance levels for the variance ratio results can depend critically on the choice of observed validation data.w}173^1^Joos,Fortunat^1992^6^Modellierung der Verteilung von Spurenstoffen im Ozean und des globalen Kohlenstoffkreislaufes^Ph.D.^University of Bern^131^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^311^^^^^^^^^^^^Physics Institute^Oeschger, H., and U. Siegenthaler^Siegenthaler, U.^DE-FG0-90ER61052/54Op?/>.OwQ},wvGcw|뿼NuA^310^A model for simulating the transport of CO{-2} and tracers in the ocean (HILDA-model) is studied. The model is latitudinally divided into two zones; in the low latitudes, transport into the deep ocean occurs by eddy diffusion, while the high-latitude zone consists of two boxes (surface and deep ocean). Different ways of calibration are compared and it is found that in order to reproduce the distribution of natural radiocarbon as well as bomb-produced radiocarbon, the vertical eddy diffusivity K must decrease with depth. The concept of eddy diffusion is discussed. The model is validated comparing m odel results of the oceanic distribution of CFCs and Ar-39 with observations. The oceanic uptake of anthropogenic CO{-2}, !biospheric CO{-2} emissions and isotopic perturbations are calculated, based on the observed atmospheric CO{-2} concentrat"ion history. The results indicate an oceanic uptake of 1.9 Gt-C/yr in 1980, and a near-zero net contribution from the biot#a in the past several decades. The HILDA-model is compared with other models, and we find that its response to atmospheric$ CO{-2} perturbations is rather similar to that of a 3-D ocean carbon cycle model of the Princeton group. The possible imp%act of a hypothetical iron fertilization on atmospheric CO{-2} levels is studies with the HILDA model. Assuming as an uppe&r limit scenario that it is possible to stimulate the uptake of abundant nutrients in the Southern Ocean, the maximum atmo'spheric CO{-2} depletion is 58 ppm after 50 years and 107 ppm after 100 years. This scenario requires completely effective( Fe fertilization to be carried out over 16% of the world ocean area. If iron fertilization were terminated, CO{-2} would )escape from the ocean and soon cancel the effect of the fertilization. The possible effect of fertilizing the ocean is sma*ll compared to the expected atmospheric CO{-2} increase over the next century, unless the increase is kept small by means of stringent measures to control CO{-2} emissions.>|8<~F#ؖI`ynFK~gf|`n [,174^1^McInnes,Barry John^1984^6^Numerical Modelling of Ice Sheet Flow and Sliding^Ph.D.^University of Melbourne^609^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^313^^^^^^^^^^^^Meteorology^Budd, W.F.^Radok, Uwe^DE-AC02-84ER60197dwuݝ.A^312^Due to the lack of precise, long-term measurements on glaciers and ice sheets, numerical modeling has become a major/ tool in probing the dynamical theory of ice masses. The available data can be used to test the theory of a model, and tun0e the various parameters included in the computation scheme. Various models of ice masses have been developed starting fro1m a simple two-dimensional glacier flowline model. Numerous additions have been made to this basic theory which allows man2y options to be chosen to invoke temperature dependent deformation velocity schemes and compute either a stable or a surgi3ng sliding velocity component. The number of options allows many test cases to be completed which give information on many4 of the lesser known parameters in the computation scheme. The information gained from these sensitivity tests allows conc5lusions to be drawn regarding the current state or mode of flow in West Antarctica and Greenland. It also provides a base 6from which additional theory can be added and its effects noted. From these investigations the dynamics of the basal sliding of ice masses can be tested to the best of our current knowledge.xoG1f,n [CFC9]w>HwC;՜8he addition of these clear sky fields also permits one to consider the cloud radiative forcing properties. The purposes of9 this paper are: 1) to study the spacial and temporal characteristics of the greenhouse effect for clear sky and cloudy sk:y conditions using the ERBE and the observed sea surface temperature data; 2) to compare the Climate Community Model (CCM1;) simulations of the greenhouse effect with the observations; and 3) to diagnose the individual contributions to the total< greenhouse effect of atmospheric trace constituents. The Earth absorbs the shortwave radiation from the sun and emits the= longwave radiation into the space. If there was no atmosphere, the longwave radiation from the Earth's surface would be t>he same as that at the top of the atmosphere. Due to the existence of water vapor, carbon dioxide, trace constituents and ?clouds, some of the longwave radiation will be trapped, thus decreasing the outgoing longwave radiation. The greenhouse ef@fect is defined as the trapping of the longwave radiation by atmospheric gases and clouds. In this paper, we evaluate the Aclear sky greenhouse effect from the model simulations of CCM1 and compare the results with the observed data over oceans.B The results show that the distribution of the monthly mean greenhouse effect from the model simulation is very similar toC that of the observational data. Both show the greenhouse effect has the maximum value of more than 175 Wm{+-2} in tropicaDl region, and the value decreases toward the polar region where it reaches 25 Wm{+-2} or less. Zonal mean profiles show smEall differences between the model simulation and observation for January and July. The global monthly average of the greenFhouse effect from observations is also close to the model analysis. We conclude that the CCM1 with trace gases in it simulGates the greenhouse very well for clear sky conditions. The interannual variability of the total greenhouse effect is founHd to be small, about 1-2 Wm{+-2}. By using a one-dimensional radiative code from the CCM1, the values of the global mean gIreenhouse effect is calculated to be 136 Wm{+-2} for July 1987 and 125 Wm{+-2} for January 1987. The model is also used toJ study the individual contributions of atmospheric constituents to the total greenhouse effect for clear sky conditions. WKater vapor, carbon dioxide, ozone, and other trace gases account for 68.6%, 21.1%, 6.6%, and 3.7% respectively for July, wLhile they are 67.5%, 22.2%, 6.3%, and 4.0% respectively for January. The results also show that the greenhouse effect is dMominated by the amount of the moisture content and its distribution. Clouds also play an important role in the climate sysNtem. Clouds absorb the longwave radiation from the Earth surface and emit it at the lower cloud top temperature. The net eOffect is to trap longwave radiation from the Earth's surface. The cloud longwave radiative forcing is defined as the diffePrence between the clear sky greenhouse effect and the total greenhouse effect. We study the cloud longwave radiative forciQng both using the model and the observational data. The model simulated patterns of the longitude-latitude distribution ofR the cloud longwave radiative forcing are in general agreement with those from observations. However, there are some discrSepancies in the magnitude and the size of the region in which cloud radiative forcing occurs. We conclude that the cloud pTarameterization in the CCM1 captures the general features of the cloud longwave radiative forcing, but further improvements are warranted.`x*b17Wp*b17Wp*b15WCx*b15WxV176^1^Zhong,Shiyuan^1992^6^An Observational and Numerical Study of Sea/Land-Breeze Circulations in an Area of Complex CoasWtal Heating^Ph.D.^Iowa State University^154^Dissertation^^^Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP)^^^^^^^317^^^^^^^^^^^^Geological and Atmospheric Sciences^Takle, Eugene S.^Takle, Eugene S.^W7405 ENG82^8YA^316^This dissertation presents an observational and a numerical study of sea/land-breeze circulations as well as a theorZetical study on the boundary-layer turbulence parameterization. The sea/land-breeze circulation is a mesoscale response of[ the atmosphere to the inhomogeneities in heating between land and water surfaces. It is a very important meteorological p\henomenon because it directly affects actual weather and climate as well as air pollution in coastal regions. Data from th]e Kennedy Space Center Atmospheric Boundary Layer Experiment have been used to examine the three-dimensional structure of ^the mesoscale Atlantic sea/land-breeze and small-scale river-breeze circulations frequently occur over the area of Kennedy_ Space Center/Cape Canaveral (KSC/CC) where there exists irregular topographic features such as rivers and lagoons. Detail`ed characteristic features over a diurnal cycle of the circulations onset time, strength, depth, propagation speed, and boath seaward and landward extensions, are documented. Some boundary-layer characteristics related to atmospheric diffusion ibncluding atmospheric stability, depth of the thermal internal boundary layer and its evolution with time, and turbulence mcixing are also discussed. One of the most important environmental factors affecting the sea/land-breeze circulation is thed large-scale synoptic forcing. Previous studies on this factor were all constrained by two factors: a) they were two dimenesional in space with the assumption of uniformity in the direction along the coastline, which is idealistic in most coastafl regions; and b) they were mostly theoretical, with little regard for geographic features that may strongly influence or gdominate the flow. A three-dimensional numerical mesoscale model is used to study the effects of synoptic forcing on the shea/land-breeze circulation at KSC/CC area. The sensitivity of mesoscale features to the large-scale background flow is expilored by examining the low-level convergence field, location, strength, and timing of maximum vertical motion; diurnal varjiation of depth of inflow layer and the thermal internal boundary layer; and the rotation of wind vector. Both of these stkudies may lead to not only an improved forecast of local weather and atmospheric diffusion of rocket exhausts at KSC/CC arlea, but also to a better understanding of the physical mechanism of the thermally induced circulations, such as their depemndence on the three-dimensional coastal effects and the synoptic forcing. Boundary-layer turbulence parameterizations are nessential for boundary-layer and mesoscale modeling. A new scheme for parameterizing the turbulent stress in terms of the omean wind profile is also presented in this dissertation. This new parameterization scheme is based on the balance of turbpulence kinetic energy and is valid in a deeper layer than the constant-flux layer where the previous schemes all fail becaquse of the violation of the fundamental assumption of constant turbulent fluxes. This new scheme may have direct impact inr boundary-layer and mesoscale modeling because it may improve the accuracy of solutions and also reduce the computation time by allowing a minimum number of vertical nodes needed to capture the sharp gradients near the low boundary.8t177^1^Li,Aiguo^1994^6^Effects of Elevated CO{-2} on Rates and Durations of Apical Development of Spring Wheat^M.S.^Universuity of Idaho^62^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^319^^^^^^^^^^^^Plant Science^Trent, Tony A.^Acock, Basil, Leon H. Allen, Jr., and Bruce A. Kimball^DE-AI05-93ER61720^1720^x8*b30W xpwA^318^Rates and durations of individual phases for wheat apex development are one of the most important factors that deterxmine the yield. The relationship between rate and duration of each phase and CO{-2} concentrations are poorly documented iyn the literature. This study was conducted to determine the rates and durations of leaf, spikelet and floret primordium inzitiation in CO{-2} enrichment system called FACE for _F_ree _A_ir _C_arbon dioxide _E_nrichment (Lewin et al., 1992). Spri{ng wheat (_Triticum aestivum_ L. cv. Yecora Roja), was planted with split block design of four repetitions at the Universi|ty of Arizona's Maricopa Agricultural Center located approximately 40 km south of Phoenix, AZ (33.075N 111.983W). The whol}eplots were 550 mol mol{+-1} enriched-CO{-2} or ambient CO{-2} concentrations. The elevated CO{-2} concentration was main~tained by FACE system. Subplots were two irrigation treatments, half of the plants received water equivalent to full water sufficiency (wet), the other half received 75% of its water needs (dry). Water was provided with sub-surface drip tube irrigation. Samples were collected about every 3 to 4 days. Two or three plants were randomly picked for apical dissection. I dissected main stem, Primary tillers: T0, T1, T2, T3, and secondary tillers: T00, T01, T02, T10, T11, and T12. After dissection, the number of primordia was counted, and length and width of apical dome were measured. Apical dimension data were fitted into exponential models as the function of accumulated thermal units. The apex primordium data were regressed against accumulated thermal units with four-piece segmented regression models with SAS proc NLIN, method Marquardt. Length of T3 and T10 apices was significantly (p<0.05) enhanced by 550 mol mol{+-1} CO{-2} enrichment in this experiment. Width of main stem, T2, T3 and T11 apices was significantly (p<0.05) increased by CO{-2} enrichment. The increased length was not accompanied by the increase in spikelet primordium number, but the width increase was accompanied by more floret primordia. I observed little or no response of leaf primordium initiation of main stem to elevated CO{-2} concentration, which might be due to low temperature at early stage, or alternatively, leaf primordium initiation was not affected by 550 mol mol{+-1} CO{-2} enrichment. Within the spikelet initiation phase, CO{-2} enrichment significantly increased rates of spikelet primordium initiation of main stem by 0.0077 spikelets per Cday and diminished the durations of terminal spikelet phase by 39.43 Cday. Spikelet initiation rates of T1, T2, T10 and T11 were significantly (p<0.05) enhanced and durations of T1, T2, T3, T10 and T11, diminished by elevated CO{-2} concentrations. Within the floret phase, CO{-2} enrichment significantly increased rates of floret primordium initiation of main stem by 0.1186 florets per Cday and diminished the durations of floret primordium initiation by 28.5 per Cday. The rates of T0, T1, T2 and T3 were significantly increased and the durations of T0, T1, T3 and T11 were significantly decreased by CO{-2} enrichment. Comparing tillers on a given plant, it appears that the development of later-formed tillers is more sensitive to CO{-2} enrichment than that of early-formed tillers. The floret primordium initiation phase is more sensitive to CO{-2} enrichment than spikelet primordium initiation phases.x*b5Wx*b5W*b5W*b5Wx*b5Wx*b5Wx*b5Wx*b5Wx*b5Wx*b5W*b5W*b5178^1^Ding,Ming^1992^6^Radiative Forcing Due to Observed Changes in Greenhouse Gases for the Period 1980-1990^M.S.^State University of New York at Albany^52^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^321^^^^^^^^^^^^Atmospheric Science^Wang, Wei-Chyung^Wang, Wei-Chyung^DE-FG02-92ER61369p8*b23W8?pp?88*b23W8?pp?88x*bA^320^Recently, satellite observation of global O{-3} distribution for the period 1980-1990 became available. The data indicated that statistically significant lower stratospheric O{-3} depletion occurred at middle to high latitudes in both hemispheres, which may perturb the radiative forcing of the troposphere-surface climate system. Here, we study the radiative forcing due to O{-3} changes and compare the value with those due to the increase in other major greenhouse gases, CO{-2}, CH{-4}, N{-2}O and CFCs over the same period. In addition, we study the direct forcing due to the CH{-4} increase and indirect due to increase in atmospheric O{-3} and stratospheric H{-2}O associated with CH{-4} increase. Stratospheric O{-3} depletion has two compensating effects on the radiation balance at the tropopause: positive solar forcing and negative infrared forcing. On a global mean basis, the radiative forcing due to the well-mixed greenhouse gases (CO{-2}, CH{-4}, N{-2}O and CFCs), CFCs and O{-3} are 0.51, 0.07, and 0.03 Wm{+-2}, respectively. Although the forcing due to O{-3} depletion is comparable to that of CFCs increase, it is small compared with the well-mixed gases. However, the calculated O{-3} forcing can be large on the basis of seasons and latitudes. For example, it may reach a maximum of 0.2 Wm{+-2} at middle latitude summer hemisphere, which is about 50% of the forcing due to well-mixed greenhouse gases. The results thus suggest that O{-3} changes can contribute significantly to the total radiative forcing. Increase in CH{-4} may lead to increases in tropospheric O{-3} and stratospheric H{-2}O, with subsequent effect on radiative forcing. We find that the radiative forcing due to the stratospheric H{-2}O increase caused by doubling the CH{-4} surface emission may enhance the CH{-4} direct effect by more than 30%. And the CH{-4}-induced atmospheric O{-3} increase may decrease the CH{-4} direct forcing by 30% at middle latitude summer hemisphere, primarily caused by stratospheric O{-3} increase. These results suggest that indirect forcing needs to be considered when addressing CH{-4} climatic effect. Finally, we carry out radiation calculations to examine the sensitivity of the radiative forcing to the climate state and the H{-2}O continuum treatment. The results indicate that both effects are small, for example, about 10% when different H{-2}O continuum schemes are used.p179^1^Zhuang,Yicheng^1993^6^Radiative Forcing Due to Observed Changes in Tropospheric Ozone^M.S.^State University of New York at Albany^84^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^323^^^^^^^^^^^^Atmospheric Science^Wang, Wei-Chyung^Wang, Wei-Chyung^DE-FG02-92ER61369 ???~~8*b143WA^322^Tropospheric ozone is observed to have increased at a rate of 10% per decade at the middle and high latitude in the Northern Hemisphere during the last two decades. This may be attributed to the increasing anthropogenic emissions of NO{-x}, CO, CH{-4}, etc. (WMO, 1991). Here, we use the observed and model-predicted tropospheric ozone trends to study their possible effect on radiative forcing, which is interpreted as a gain (positive) or loss (negative) of radiation energy for the surface-troposphere system as a whole. The radiative forcing caused by ozone changes is calculated as the changes in the net downward radiative flux at tropopause. Because the observed lower stratospheric ozone depletion may induce a cooling of the lower temperature, we use two types of treatment to calculate the radiative forcing: the first is the fixed temperature treatment, and the second is the fixed dynamical heating treatment, in which the temperature is determined under radiative equilibrium condition with constant dynamical heating. The observed ozone data were measured from seven ozonesonde stations in the Northern Hemisphere, while the model-calculated tropospheric ozone changes were provided from simulations using as two-dimensional tropospheric photochemical tracer transport model at University of Oslo, Norway. Tropospheric ozone increase would result in more absorption of both solar and terrestrial radiation, and therefore yields a warming of the troposphere-surface system. Our study showed that at the stations where there was a large tropospheric ozone increase in the last one to two decades, the fixed-temperature forcing caused by the tropospheric ozone trend was comparable to or even greater than the forcing caused by the stratospheric ozone depletion, thus indicating that the warming effect caused by the tropospheric ozone increase could be as significant as that caused by stratospheric ozone depletion. For example, in January at Payerne, the fixed-temperature forcing caused by the tropospheric ozone increase is 0.24 Wm{+-2}, more than twice the forcing caused by the stratospheric ozone depletion which is 0.11 Wm{+-2}. The fixed-dynamical heating forcing include an additional cooling effect of the troposphere-surface system caused by the decreased long wave radiation flux to the troposphere resulting from stratospheric temperature decrease in response to stratospheric ozone depletion. This additional cooling effect varies from 0.02 Wm{+-2} to 0.32 Wm{+-2}, depending on the magnitude of the stratospheric ozone depletion. Consequently, compared with the fixed temperature treatment, the fixed-dynamical heating treatment will calculate a relatively more important role of tropospheric ozone increase. Comparing the forcing induced by the observed ozone changes and CO{-2} increase during the last two decades, we find that the total ozone induced forcing can attribute substantially to the tropospheric ozone increase, which is comparable to or even exceeds the CO{-2} induced forcing. For example, in July at Hohenpeissenberg the fixed-temperature forcing (0.57 Wm{+-2}) caused by ozone is more than twice of the forcing caused by CO{-2}. It is therefore concluded that the increasing trend of tropospheric ozone may have significant climate implications. Changes of the tropospheric ozone for the period 1990-2025 are calculated from a two-dimensional photochemical model. Four cases are considered: (1). CH{-4} emissions increase by 10%, (2). CO emissions increase by 10%, (3). NO{-x} emissions from ground sources increase by 10%, and (4). NO{-x} emissions from airplanes increase from 0.7 TgN/yr to 1.2 TgN/yr. The maximum increase in the model-predicted ozone is 4% around 10 km for case 4. Consequently, the radiative forcing is also small ranging from 0.02 Wm{+-2} to 0.19 Wm{+-2}, which is about 10-20% of the forcing caused by CO{-2} increase during the same time period. The much smaller ozone changes calculated for the next two decades are not consistent with the large observed increase for the past two decades. Therefore, there are two needs to address this issue: The first is to understand better the causes for the ozone increases and the second to continue improving the models for their representation of physical and chemical processesp8*b26Wp8*b26Wp8*b180^1^Renn,Nilton de Oliveira^1992^6^Cumulus Convection Parameterization and Numerical Modelling of Moist Atmospheres^Ph.D.^Massachusetts Institute of Technology^297^Thesis^^^Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP)^^^^^^^325^^^^^^^^^^^^Earth, Atmospheric, and Planetary Sciences^Emanuel, Kerry A.^Emanuel, Kerry A.^DE-FG02-91ER61220.A002A^324^A hydrological cycle is explicitly included in a one-dimensional radiative-convective equilibrium model which is coupled to a "swamp" surface and tested with various cumulus convection schemes: the Moist Convective Adjustment scheme (Manabe et al., 19656), the Kuo (1974) scheme, the GISS (1974) Model scheme, the GISS (1983) Model II scheme, and the Emanuel (1991) scheme. Our results show that when the flux of incoming solar radiation is above a critical value dependent on the choice of the cumulus convection scheme equilibrium is not possible (a runaway greenhouse occurs). When the atmosphere's relative humidity is kept fixed at climatological values, the runaway greenhouse is inhibited. Furthermore, while the mass flux schemes [GISS (1974), GISS (1983), and Emanuel (1991)] produce an abrupt runaway greenhouse which occurs through a finite amplitude instability generated by the interaction of infrared radiation fluxes with detrained water vapor at the level of neutral buoyancy the other schemes produce a smooth transition to the runaway greenhouse. In addition, our results show that the Moist Convective Adjustment scheme breaks down when the runaway greenhouse is approached, and that the various cumulus schemes tested produce a decrease in the relative humidity of the middle-upper troposphere when the atmosphere's CO{-2} content is doubled. These schemes are not consistent with each other since they not only lead to different critical solar forcing for a runaway greenhouse to occur, but also produce very different water vapor profiles in the equilibrium atmosphere and have different lapse-rate feedbacks. Finally, using the scheme proposed by Emanuel (1991), we show that the atmospheric water vapor content and, therefore, the sensitivity of the equilibrium temperature to changes in the solar forcing, as well as the critical solar forcing in order for the runaway greenhouse to occur, depend crucially on the microphysics of cumulus convection. These results indicate that a physically-based cumulus convection scheme is of crucial importance in climate simulations, and that a poor cumulus convection scheme can produce artificial sensitivities in numerical simulations of moist atmospheres.Wp8*b19Wp8*b19Wp8*b19W8*b19Wp8*b19Wp8@*b19Wp8*b19Wp8*b19WpA^326^Net carbon exchange (NCE) was measured on a burned and unburned tallgrass prairie canopy during a four month period in 1987. NCE rates were higher on the burned treatment (0.66 mg CO{-2} m{+-2}sec{+-1}) compared to the unburned treatment (0.47 mg CO{-2} m{+-2}sec{+-1}) on 11 July. On 20 July NCE rates were higher in the unburned treatment 0.64 mg CO{-2} m{+-2}sec{+-1}) than the burned treatment (0.38 mg CO{-2} m{+-2}sec{+-1}). Maximum NCE rates on 15 August were 0.37 mg CO{-2} m{+-2}sec{+-1} and 0.47 mg CO{-2} m{+-2}sec{+-1} in the burned and unburned treatments, respectively, but not significant differences existed between treatments. Plants were not light saturated at 1900 E m{+-2} sec{+-1} on 15 August. Canopy NCE rates were generally lower than rates measured on individual leaves of _Andropogon gerardii_ (big bluestem). No consistent differences in soil water content or leaf water potential were measured between burned and unburned treatments. The highest measured midday leaf water potential was -1.56 MPa in the unburned treatment on 14 July, but had declined to <-4.0 MPa in both treatments by 21 July. Soil CO{-2} flux decreased as soil water content declined, reaching a low of 0.06 mg CO{-2} m{+-2}sec{+-1}, but increasing under higher soil water content to 0.16 mg CO{-2} m{+-2}sec{+-1}. Soil CO{-2} flux was 7 to 28% of the net photosynthetic flux. Differences in photosynthetic rate can probably be attributed to differences in incident solar radiation as well as morphological differences between plants emerging in sun (burned) or shade (unburned) environments.*b19Wp8*b19Wp8@*b19Wp8*b19Wp8*b19WA^329^Growth and biomass accumulation of rooted _Citrus limon_ Hort. 'Eureka" cuttings, after inoculation with either arbuscular mycorrhizal fungal populations originating from a plains grassland or Sonoran desertscrub biome, were measured after 3 months of growth in factorial combinations of near-optimal (29.4 C day max/21.1 C night min.) or supraoptimal (40.5 C day max./32.2 C night min.) diurnal temperature cycles and ambient (350-380 mol mol{+-1}) or enriched (650 mol mol{+-1}) atmospheric CO{-2} concentrations. Shoot growth and root to shoot ratio were affected by an interaction of temperature and CO{-2} treatments. Supraoptimal temperatures suppressed shoot extension growth and leaf accumulation; however, this heat-induced growth suppression was alleviated by a near doubling of atmospheric CO{-2}. At near-optimal temperatures, shoot growth of CO{-2}-enriched trees and those grown under ambient CO{-2} condition was similar. At near-optimal temperatures, root to shoot ratio was less for CO{-2}-enrichment trees compared with trees grown at ambient CO{-2}. Conversely, root to shoot ratio at supraoptimal temperatures of CO{-2}-enriched and trees grown under ambient CO{-2} conditions was similar. Temperature was the sole factor affecting mycorrhizal colonization of 'Eureka' lemon tree roots. Supraoptimal temperatures decreased total root colonization but increased arbuscular colonization relative to near-optimal temperatures. Shoot and root growth were also affected by an interaction of temperature and different ecotype populations of arbuscular mycorrhizal fungi. At near-optimal temperatures, lemon tree leaf area to root length ratio was not affected by mycorrhizal treatments, but at supraoptimal temperatures, there was a 37% greater leaf area to root length ratio in trees inoculated with the plains grassland population of AM fungi compared with those trees inoculated with the Sonoran desertscrub population of AM fungi. These data suggest that benefits of the mycorrhizal symbiosis may not necessarily be based on growth enhancement of the host plant. - - -     els, increases soil carbon inventories. This research introduces a "greening" model to estimate this increase, using a CO{ -2} fertilization factor, active soil carbon inventory, and turnover time. This research also uses radiocarbon measurement s to examine how cultivation reduces the inventory of active soil carbon. Further, the relationships between carbon loss a nd vegetation type, farming technique, and the clay content of soil have been examined to identify patterns that can be us ed to develop strategies for mitigating future carbon loss. Formerly cultivated lands that are undergoing secondary succession can sequester atmospheric carbon. This research extends previous work in this area. One coniferous site in this study had a higher soil carbon inventory than its native deciduous counterpart. Anthropogenic nitrogen deposition, like CO{-2} fertilization, may also increase soil carbon storage. This research sets limits on the amount of carbon sequestered by nitrogen deposition by determining the amount and fate of anthropogenic nitrogen. In summary, CO{-2} fertilization and N-deposition can potentially sequester a major portion of the so-called missing sink. This research identifies ways to limit biospheric carbon loss and enhance carbon recovery on formerly disturbed lands.*b155WA^333^This study examines the Time/Space Averaging (TSA) process applied to scanner measurements of the Earth Radiation Budget Experiment. The TSA process produces monthly averages from the temporally sparse flux measurements on a regional scale. The diurnal distribution of the ERBS flux measurements for a given month and region shows considerable bias in high latitudes due to the inclination of the ERBS satellite orbit. The ERBS measurements for 72 days (approximately the processing period of the ERBS satellite orbit) have a nearly complete diurnal distribution for each region between 60N-60S. To examine the TSA process, simple averages obtained from two 72-day measurement sets in 1985 and 1986 are assumed as the expected true averages. For clear-sky, simple averaging methods are employed to infer the true averages where one can expect a diurnal sampling bias due to clouds. The TSA process is examined in detail for different data sets of ERBS and NOAA 9. This report shows that the TSA process is adequate to account for the diurnal variation of radiation for both ERBS and NOAA 9 clear-sky measurements. The monthly clear-sky longwave flux differences between ERBS and NOAA 9 are explained mostly by the ERBS diurnal sampling bias and the different scene identification procedures for daytime and nighttime. When applied to NOAA 9 cloudy-sky measurements, considerable errors result in the summer hemisphere. This is due to the substantial diurna l variations of cloud properties and the NOAA 9 sampling at only around 2:30 and 14:30 local time in most latitudes. For E!RBS cloudy-sky measurements, the above errors are seen to be reduced significantly because of better diurnal sampling. A s"imilar examination is suggested for the case of NOAA 10, the third ERBE satellite, which samples at around 7:30 and 19:30 local time in most latitudes.EY BIB B1JRNL BIB S{U1KEY BIB B1 $186^1^Chen,Minghang^1993^6^Cloud Radiative Forcing Anomalies Associated with and Their Effects on the Atmospheric Response% to Equatorial Pacific SST Anomalies^Ph.D.^State University of New York at Stony Brook^142^Dissertation^^^Carbon, Climate,& and Vegetation^^^^^^^336^^^^^^^^^^^^Coastal Oceanography (Atmospheric Sciences)^Cess, Robert D.^Cess, Robert D.^DE-FG02-85ER60314~?*b211W?8?~x?~~pp?(A^335^The NCAR CCM2 has been used in this study to investigate cloud radiative forcing (CRF) anomalies associated with equ)atorial Pacific SST anomalies, and the effects of the longwave CRF (LWCRF) anomalies on the atmospheric response to the SS*T anomalies. The SST anomalies cause large CRF anomalies, both longwave and shortwave, as well as latent heat anomalies at+ low latitudes on a global scale. The relative magnitude of the simulated longwave and shortwave CRF anomalies is consiste,nt with the result of the Earth Radiation Budget Experiment (ERBE), which means cloud height and cloud radiative propertie-s, such as emissivity and reflectivity, are well simulated by the model. The CRF anomalies, however, are underestimated in. the CCM2. This underestimate of the CRF anomalies is due to the insufficient high cloud amount anomaly in the model. The /LWCRF anomaly strongly enhances the precipitation anomaly in the whole tropical belt. The positive (negative) LWCRF anomal0y warms (cools) the troposphere and destabilizes (stabilizes) the upper troposphere. The LWCRF anomaly enhances the Southe1rn Oscillation, both the positive sea level pressure (SLP) anomaly in the Indonesia-Australia region and the negative SLP 2anomaly in the central and eastern Pacific, and the related Walker circulation anomaly. The effects of the LWCRF anomaly a3re essential to the NH extratropical circulation anomaly, the PNA pattern. The LWCRF anomaly has a large contribution to t4he three action centers of the PNA pattern, especially the positive anomaly center, at all levels. This large contribution5 results from the direct thermal effect of the tropical LWCRF anomaly and its strong positive interaction with tropical de6ep convection. As a consequence of the complex interaction between the forced wave train, orographic forcing and other factors, the contribution rates of the LWCRF anomaly to the three PNA action centers are different.8 ~ 8187^1^Dlhopolsky,Rose Marie^1991^6^A Study of the Earth Radiation Budget Experiment Short Wave Measurements and Bidirectio9nal Reflectance Models for the Ocean Surface^Ph.D.^State University of New York at Stony Brook^141^Dissertation^^^Carbon, :Climate, and Vegetation^^^^^^^338^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Cess, Robert D.^Hameed, Sultan^DE-FG02-85ER603148  *b70W@@x@~@P the angle at which a scene is being observed and the position of the sun relative to that scene and the satellite. In thi?s study, reflectances are derived from Earth Radiation Budget Satellite (ERBS) shortwave radiances and sorted according to@ the range of angles at which they were measured. This range is called the angular bin size. The Nimbus 7 Bidirectional ReAflectance Models were created using this same procedure. In this study, the size of the angular bins is made smaller than Bthe sizes in the Nimbus 7 Bidirectional Reflectance Models in order to more accurately describe the angular dependence of Cthe shortwave reflection. Results indicate that the size of the Nimbus 7 angular bins causes the ERBE shortwave fluxes to Dbe overestimated when the satellite views specular reflection from the ocean surface. This is especially severe for solar Ezenith angles less than 25 degrees. Clear sky shortwave radiances measured under specular geometries are very large and arFe therefore not included in the processing. However, these radiances are sometimes identified as clouds and included in thGe data set. This occurs because shortwave radiances reflected from clouds do not exhibit as strong a dependence on viewingH geometry as the clear sky ocean surface. Therefore, a large shortwave radiance is identified as a cloud. Examples are given where this affects the regional data.n and prescribed sea-surface temperatures. Thornthwaite's scheme also detected noJ188^1^Subasilar,Bedrettin^1991^6^The Broad Band Overlap Problem in Atmospheric Trace Gases^Ph.D.^State University of New YKork at Stony Brook^118^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^340^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Cess, Robert D.^Cess, Robert D.^DE-FG02-85ER60314the model climate because of the level of noise and the dMA^339^In relation to a better understanding of climate change and the related greenhouse problem, one way of projecting foNr the next decades is through general circulation models (GCMs). The only input as a driving force in the changing atmosphOeric and oceanic circulation patterns is the amount of heat perturbation either due to natural or man-caused activities. APmong these, CO{-2} concentrations resulting from the latter has been observed to be accelerating at alarmingly high rates Qespecially after the advent of the industrialization which just began in the last century. In addition to that, collectiveR effects of other greenhouse gases (freons, SO{-2}, H{-2}O, CH{-4}, etc.) are as important as CO{-2}. Hence, it is evidentS from the above considerations that, in the predictions of climate models, the heat input which triggers changes in the atTmospheric patterns, should be formulated accurately. In order to realize this objective, in this research,beginning with tUhe available line parameter data, the problems of absorption have been investigated and attacked in the frame known as theV broad band modeling since that is the only best and fastest manageable representation for GCMs. The first step was the coWnstruction of a full broad band (intra band overlap) model that was also flexible enough to accommodate the individual pecXuliarities of the bands. Before, the well known and very useful Ramanathan model had a limited applicability in the concenYtration scale, and it was also not systematically, or successfully incorporated into an inter band overlap picture. Then, Zthe established ideas that served as bases up to present, have been employed but found to have a limited practical applica[bility when it came to predict the inter band overlaps. This followed by the clarification of the probabilistic approach, \each of which are already shown to be expressible in terms of full broad bands, gave rise to the recognition of the transm]ittance multiplication principle being applicable to the wider than narrow-band segments or the whole bands. At the end, an example of a flux application is added._189^1^Kim,Yongseung^1991^6^Sulfate Impact upon Low-Level Cloud Albedo over Oceans^Ph.D.^State University of New York at St`ony Brook^161^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^342^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Cess, Robert D.^Cess, Robert D.^DE-FG02-85ER60314 Robert D.^DE-FG02-85ER60314bA^341^The Earth Radiation Budget Experiment (ERBE) NOAA-9 scanner measurements have been employed for the purpose of identcifying cloud albedo change due to continental sulfur emissions in the Northern Hemisphere. Comparison of cloud albedo overd two hemispheric oceans has been made based on the hemispheric imbalance of the anthropogenic sulfur emissions that existse. The present study shows that cloud albedo, particularly in the broad maximum region of sulfur emissions off the east coafsts of North America and Asia, appears to be affected by the land-transported sulfate aerosols. Although the continental sgulfate aerosols substantially modify the marine low-level cloud albedo off the coasts, their dominance over the central ochean appears to be uncertain. The primary source of cloud albedo variations over the central ocean are considered to be phyitoplankton chlorophyll concentrations, sea surface temperature (SST) and solar zenith angle (SZA). The correlation analysijs, using chlorophyll concentrations derived from the Coastal Zone Color Scanner (CZCS) and the climatological SST data, rekspectively demonstrates that these two variables explain substantial variations of cloud albedo over the central ocean. However, the SZA effect upon the cloud albedo vs. longitude pattern is shown to be negligible. m190^1^Zhang,YingYi^1992^6^Two Studies on the Sources and Reactions of Tropospheric Gases: Investigation of Emission of Tronpospheric Gases in Biomass Burning and the Effects of Diurnal Variation of Photolysis Rates on Their Concentrations^M.S.^Sotate University of New York at Stony Brook^71^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^344^^^^^^^^^^^^Marine Environmental Sciences Program^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314qA^343^In May 1989, a major fire began in the Great Hinggan Forests in Heilongjiang province in Northeastern China and acrorss the Black Dragon River in Siberia. A detailed investigation of the fire by Yang et al. (1987) suggested that the total sarea burned in China was about 2.8 million acres. Based on their information, this study estimates the release of CO{-2} atnd CO from this fire to be about 73 Tg CO{-2}-C and 7.3 Tg CO-C, together with 0.84 Tg CH{-4}-C, 0.85 Tg NMHC-C, 0.35 Tg Hu{-2}-H, and 0.027 Tg N{-2}O-N. By comparing these values with estimated releases from tropical areas and emissions from fovssil fuel combustion, we know that this big boreal forest fire contributed significantly to the total release of CO{-2} anwd CO and other trace gases to the atmosphere. Comparisons between two zero-dimensional photochemical models have shown thaxt the concentrations of many tropospheric species are very sensitive to photolysis rates of ozone, nitrogen dioxide and seyveral other species by UV radiation on the 290-400 nm region. An accurate calculation of the associated photolysis rates izs essential in model descriptions of the troposphere, as is the diurnal variation of photolysis rates and their impact on {the calculated concentrations of trace species in the troposphere. Using newly published, presently recommended absorption| cross section and quantum yield data, updated photolysis rates for tropospheric species have been obtained. By comparing }concentrations computed using diurnal variation of photolysis rates with concentrations derived using diurnally averaged c~alculation. this study showed the diurnal variation of photolysis rates is very important in determining the tropospheric concentrations of NO{-3} and N{-2}O{-5}. Nadezda 11Wilbanks Tom 191^1^Pittalwala,Iqbal Ibrahim^1993^6^Evolution of the North Atlantic Oscillation^Ph.D.^State University of New York at Stony Brook^202^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^346^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314C:\WP51\DOCS\REV13.GEN Using Format: THESISIN Fussiness Level: FinA^345^The year-to-year variations of winter climate of the North Atlantic region including Northern Europe, northwest Africa and North America are largely influenced by the phases of the North Atlantic Oscillation (NAO). The NAO has been examined using winter sea-level pressure data and an index has been formulated that captures the variation of its intensity. The oscillation is shown to be detected in a coupled ocean-atmosphere general circulation model. The simulated teleconnections in the peripheral land masses of the North Atlantic Ocean are compared with observations. It is suggested that explanations of these climatic variations may be found through diagnoses of such model simulations. The evolution of the NAO has been investigated by inspecting the progression of sea-surface temperature (SST) and sea-level pressure (SLP) anomalies for the high and low phases of the oscillation. The progression of the anomalies is found to be generally similar but with opposite sign in the two phases. The high phase is foreshadowed by a major reversal of sea-level pressure conditions in the Icelandic Low region in October. Analyses indicate that the high phase is characterized by a distribution of warm water in the central portion of the North Atlantic. This warm water is flanked by anomalously cold water is the north and in the tropics and subtropics. This distribution is explained as a consequence of the intensification of currents in the Atlantic gyres which is related to the strengthening of the Azores High and Icelandic Low. This explanation is supported by the OSU GCM simulation. the change in terms of what type of vegetation could be supported. They also have the potential for d 192^1^Pittalwala,Iqbal Ibrahim^1988^6^Spatial and Temporal Variations in United States Sunshine^M.S.^State University of New York at Stony Brook^85^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^348^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314... Filed as Ref# 15 "Jiang, Xingjian","1986","Role of OceA^347^Sunshine duration measurements have been made in the United States for about a hundred years, the data consisting mainly of monthly percentages of possible sunshine hours at more than 200 stations. Sunshine recording instruments were changed throughout the country to the photoelectric switch in 1953. The data were subjected to tests that investigated possible contamination of the time series due to changes in instrument. The results indicate that any inhomogeneities in the mean monthly, seasonal or annual values of sunshine duration, attributable to the instrument change, are not significant. Trend analysis was performed for nine climatic subdivisions of the United States for the period 1908-1984 to discern temporal and spatial changes in the availability of sunshine. Sunshine for a 30 year period in the nine subdivisions were compared with the Institute of Atmospheric Physics General Circulation Model regional sunshine predictions. A qualitative comparison has also been made with 1971-81 monthly and seasonal cloud cover data for the contiguous United States.O2 simulation. T193^1^Sperber,Kenneth Robert^1985^6^Characteristics of Removal and Deposition of Soluble Species by Precipitation^M.S.^State University of New York at Stony Brook^143^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^350^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314^ it i s not sufficient to compare the simA^349^The scavenging coefficient in air, lambda, for nitrate, sulfate and ammonium have been estimated under a variety of meteorological and seasonal conditions from comparing the respective deposition of the species in successive hours of precipitation samples taken over a six year period at Brookhaven National Laboratory, Long Island, New York. The square root transformation of the scavenging coefficients, lambda{+}, yields an approximately normal distribution for each species. The mean value of the nitrate scavenging coefficient is 1.18 x 10{+-4} sec{+-1}, for sulfate 0.92 x 10{+-4} sec{+-1}, and for ammonium 1.41 x 10{+-4} sec{+-1}, in general agreement with previous experimental and theoretical estimates. An interesting property of the distribution of the scavenging coefficients is that the ratio of the mean value of lambda{+} to its standard deviation varies little from 2.4 for nitrate, ammonium and sulfate for meteorological subsets of the data. This property may limit the choice of stochastic models which may describe the scavenging process. A trend analysis of the relationship between the scavenging coefficient and rainfall rate indicates that the nitrate scavenging rate increases with rainfall rate for rainfall rates >3.4 mm/hr, qualitatively similar to model predictions in this region but based upon a small number of data points. The sulfate and ammonium scavenging coefficients are not simple functions of rainfall rate, their behavior is similar due to their prior association as (NH{-4}){-2}SO{-4}. The length and variability of a mean precipitation period and dry period are approximately a factor of two greater at BNL as compared with Whiteface Mountain (WFM) from comparison of six years of precipitation data obtained at BNL and five years of data from WFM. The scavenging coefficient estimates combined with the precipitation and dry period data indicate residence time estimates for soluble pollutants are most sensitive to the mean length dry periods for estimates of lambda 10{+-4} sec{+-1}. The deposition and concentration of nitrate, sulfate and ammonium with wind direction is investigated indicating greater concentration and deposition when hourly averaged winds are from the west.ds, two for Rayleigh scattering and ozone absorption, and one for water vapor a194^1^Kirkyla,Kristina Irena^1988^6^Harmonic Analysis of Global Precipitation: A Comparison Between a General Circulation Model and Observations^M.S.^State University of New York at Stony Brook^135^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^352^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314tion of clouA^351^Using precipitation values obtained from a version of the Oregon State University General Circulation Models and observational gridded data, harmonic analysis has been employed to study the seasonal variation of precipitation over various regions of the globe, including conterminous United States, South and Central America, Europe, Asia, Australia and Africa. Maps of primarily the first and second harmonic amplitudes, and the corresponding maxima provide a useful source of comparison between model output and observational data. Results indicate that the method of harmonic analysis allows a more analytical comparison between model predictions and data than the conventional approach of representing the annual march in the form of a curve of mean monthly rainfall amounts. The method delineates regional boundaries of various precipitation regimes, highlighting regions of transition. It is seen that the GCM captures a significant amount of regional detail in precipitation climatology when its results are decomposed by harmonic analysis.inment layer, a =3D 10; and (3) the conversi195^1^Knipl,Lisa Anne^1988^6^A Time Series Analysis of Precipitation Records in China from 1470-1979^M.S.^State University of New York at Stony Brook^104^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^354^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314 that the cloud-radiation para meterization is capable A^353^A time series analysis using the method of Fourier transforms is performed on twenty-six precipitation records from Northeast China over the period of 1470-1979. The large quantity of data present has permitted the detailed investigation of the nature of the background spectrum of the series and the distribution of the spectral density over particular frequencies. An analysis of the power spectra reveals that the background spectrum is more closely related to white noise than to red noise which is commonly used in the time series analysis of climatic variables. A Fourier analysis is performed on a large number of random series in order to examine the distribution of spectral estimates over a particular frequency. Experimentation shows that the distribution of spectral lines due to random fluctuations is indeed the theoretically proposed chi square distribution. This idea was then applied to certain frequencies of the Chinese precipitation data. The distribution of spectral estimates for frequencies corresponding to 18.6, 22.2, and 10.4 years was seen to be significantly different from that of chi square. Therefore it may be concluded that fluctuations in the Chinese precipitation at periods of 18.6, 22.2, and 10.4 years have some physical causes and are not random fluctuations.rs were generated by the OGCM during 196^1^Nemesure,Seth^1991^6^The Impact of Clouds on Atmospheric Shortwave Radiation at the South Pole^M.S.^State University of New York at Stony Brook^60^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^356^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Cess, Robert D.^Cess, Robert D.^DE-FG02-85ER60314 Robert D.^DE-FG02-85ER60314uced climate changes showsA^355^Two separate datasets both of which provide measurements of net downward shortwave radiation have been combined, so as to provide a means for critically examining how antarctic clouds impact the shortwave radiation budget of the surface atmosphere system and also the atmospheric column. The near-surface measurements are made by NOAA's Geophysical Monitoring for Climate Change at the South Pole Observatory while the top-of-atmosphere measurements are made by the Earth Radiation Budget Experiment aboard the NOAA-9 satellite. In addition, a delta-Eddington shortwave atmospheric radiation model is used to help interpret and understand these datasets. The datasets indicate that there is a negative correlation between planetary albedo and surface insolation within a small range of solar zenith angles. This implies that cloud-radiative forcing at the South Pole is negative. Using the linear slope-offset relation between net downward shortwave radiation at the top-of-atmosphere and at the surface, the shortwave radiative impact of clouds on the atmospheric column was also shown to be a cooling. Finally, this linear slope-offset relation has shown that clouds do not appear to effect the transfer of shortwave radiation from the top-of-atmosphere to the surface.113W8~<? ~< 197^1^Dignon,Jane Elizabeth^1988^6^Time and Spatially Dependent Estimates of Pollutant Trace Gas Emissions and Their Effect on Tropospheric Ozone^Ph.D.^State University of New York at Stony Brook^180^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^358^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314p8A^357^Statistical models have been developed to relate the rate of pollutant emissions to the rate of fuel combustion. These models have been used to estimate global emissions of nitrogen and sulfur oxides in fossil fuel combustion since the year 1860. When averaged over the 1860 to 1980 period, global sulfur emissions increased at a rate of 2.9 percent per year, and the nitrogen emissions increased at a rate of 3.4 percent per year. Using these statistical models along with population distribution estimates, high resolution geographical maps of emissions can be produced for each year which fuel consumption data are available. Global emissions of NO{-x} and SO{-x} emissions for 1966 and 1980 are illustrated on a latitude-longitude grid appropriate for general circulation models of the atmosphere. Emissions of carbon monoxide from fossil fuel, wood and biomass fuel, and open burning of vegetation, as well as emissions of nitrogen and sulfur oxides from wood and biomass fuel burning, are estimated for 1980 using emission factor methods. These trace gas sources are also mapped globally. The impact of increasing emissions of NO{-x} on tropospheric ozone abundance is estimated by calculations with a one-dimensional (latitudinal) model which includes coupled tropospheric photochemistry and diffusive meridional transport. Steady-state photochemical calculations with the prescribed NO{-x} emissions appropriate for 1966 and 1980 indicate an ozone increase of 8 to 11 percent in the Northern Hemisphere, a result which is compatible with the rise of about 12 percent between 1970 and 1981 suggested by recent observations.8<p < 198^1^Sperber,Kenneth Robert^1989^6^Southern Oscillation Simulation in Coupled Ocean/Atmosphere Global Climate Models^Ph.D.^State University of New York at Stony Brook^156^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^360^^^^^^^^^^^^Mechanical Engineering (Atmospheric Sciences)^Hameed, Sultan^Hameed, Sultan^DE-FG02-85ER60314 8A^359^The Southern Oscillation is a major component in the interannual variations of global climate. The Oregon State University Global Climate Model with a dynamically interactive upper ocean reproduces in qualitatively correct fashion the major characteristics of the Southern Oscillation. This model simulates the observed anti-correlation of annually averaged sea-level pressure between the eastern Pacific and the Indonesian region, the primary atmospheric signal of the Southern Oscillation. During the first half of the calendar year positive sea-surface temperature (SST) anomalies propagate eastward towards South America from the tropical western Pacific. The SST anomalies develop in conjunction with the eastward mixed layer current anomalies in the tropical Pacific. In the late summer/early fall anomalously warm water near South America develops and moves westward to merge with the central Pacific anomalies. This lagged development in the eastern Pacific is qualitatively analogous to the 1982/83 El Nio. The temperature of the thermocline layer also increases, with the slope of the equatorial Pacific thermocline decreasing in response to the relaxation of the trade winds. Enhanced precipitation occurs in the mid-Pacific while in Indian and Australian monsoon regions a deficit occurs. For this phase of the oscillation the model predicts anomalous currents in the Arabian Sea which oppose the usual flow. The decay of the warm phase occurs in mid/late northern winter, somewhat earlier than observed during El Nios. The cold phase of the Southern Oscillation, enhancement of the zonal circulation, evolves in a fashion similar to the warm phase with the sign of the anomalies reversed, similar to the observations. Comparison with a slab version (no ocean dynamics) of the GCM indicates that the Southern Oscillation has its genesis in the atmosphere during northern spring and dynamic ocean interactions act to propagate this atmospheric impetus to other seasons. Southern Oscillation generation in the GCMs indicates that high frequency ocean waves are not necessary for this phenomenon to occur as suggested by Pacific Basin Models. These results also show that ocean/atmosphere global climate models are useful tools for investigation of time dependent changes on the interannual timescale 200^1^Prentice,Katharine Culbertson^1986^6^The Influence of the Terrestrial Biosphere on Seasonal Atmospheric Carbon Dioxi de: An Empirical Model^Ph.D.^Columbia University^247^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^363^^^^^^^^^^^^Geography^Zobler, Leonard^Fung, Inez^DE-AI05-83OR21383cedent cumuloform cloud. The parameters for the cumuloform-cloud par A^362^A simple global model of the seasonal exchange of CO{-2} between the biosphere and the atmosphere has been developed . The model is climate-driven allowing vegetation types as well as carbon fluxes to adjust to perturbed climates. Output f rom the model consists of two fluxes - one directed toward the biosphere the other directed toward the atmosphere. The pre scription for change in vegetation type in response to climate change is based on annual temperature and precipitation. Th e carbon fluxes are based on published field and laboratory measurements of photosynthesis and soil respiration, which hav e been empirically related to climate variables. The biosphere-atmosphere exchanges are tested by comparing predicted atmo spheric CO{-2} concentrations with observations at a number of monitoring stations. Because the model incorporates spatial and temporal variability of vegetation at climate modeling resolution, the carbon fluxes are biologically more realistic than those of earlier global biospheric carbon models. This research is a first step toward relating climatic variables to seasonal properties of vegetation which influences atmospherically-important biospheric exchanges.ction of the subtropic 201^1^D'Arrigo,Rosanne Dorothy^1989^6^Dendrochronologic Modeling and Reconstruction of Large-Scale Climate Variability in Recent Centuries and Its Relation to Atmospheric Forcing Functions^Ph.D.^Columbia University^216^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^365^^^^^^^^^^^^Geology^Jacoby, G.^Fung, Inez^DE-AI05-83OR21383^racer Experiment With an Atmos A^364^Tree-ring chronologies from boreal treeline and other sites have been used to reconstruct patterns of climate variab ility, their relationship to known forcing functions, and climate as modeled using these forcings. Northern Hemisphere tem peratures reconstructed for the past three hundred years agree with other proxy data and with temperature derived from a r adiative-convective model incorporating volcanic, solar and CO{-2} forcings. Superposed epoch analysis shows the effects o f volcanism on tree growth and spectral analysis indicates periodicities which might be related to solar or other cycles. Comparison of the reconstructed temperatures with recent instrumental records reveals that the temperature departures with in the past decade of elevated atmospheric trace gases levels exceed the "natural" variations in the tree-ring data in pas t centuries. A CO{-2} fertilization effect is not detected in this data through 1973. This issue is further investigated f or a high-elevation lodgepole pine site from California. Climate response models indicate that a recent growth increase ca nnot be completely explained by past climate-growth relationships. The contribution of atmosphere-biosphere CO{-2} exchang e of boreal forests to Pt. Barrow CO{-2} amplitudes is found to be significant using a 3-D tracer model which employs an e xchange function based on remote sensing photosynthetic indices. Positive correlations between variations in those amplitu des and tree-ring data suggest that tree-rings may be used as indicators of CO{-2} uptake and remote sensing estimates of photosynthetic activity. The northern chronologies show patterns of variation which have climatic implications. Their coef ficient of variation reveals periods of agreement/disagreement among the sites which in turn indicates varying periods of !spatial coherence in atmospheric circulation patterns. Included among the years of highest variation is 1816, one year fol "lowing the Tambora eruption. The tree growth anomalies support the hypothesis of a shift in the atmospheric long wave patt #ern with enhanced meridional Arctic airflow at this time. Internal variations of the climate system include the global-sca $le interactions associated with the El Nino-Southern Oscillation and variations in the monsoon cycle. A Java teak tree-ring series shows a response to ENSO and monsoon precipitation.hange, and 70-160 years for passive CO2-induced climate chang &ship was found to be strongly influenced by solution pH, the nature of the suspended solids as well as the amount of other natural cations present in the system.of the CO2-induced heating and passive tracers show that there is no a single trac (202^1^Dugue,Charles Pierre Michel^1989^6^Colloidal Behavior in Natural Waters as Described by Ultrafiltration^M.S.^Illinoi )s Institute of Technology^52^Thesis^^^Terrestrial Transport^^^^^^^367^^^^^^^^^^^^Environmental Engineering^Holsen, Thomas M.^Gaffney, Jeffrey S., and Nancy A. Marley^W-31-109-ENG-38^udy. The carbon-cycle study shows that the model is capable o +204^1^Kawase,Mitsuhiro^1986^6^Circulation and Nutrients in the Atlantic Ocean^Ph.D.^Princeton University^145^Dissertation^ ,^^Carbon, Climate, and Vegetation^^^^^^^371^^^^^^^^^^^^Geophysical Fluid Dynamics Program^Sarmiento, Jorge L.^Sarmiento, Jorge L.^DE-FG02-90ER61052present study. The model-simulated ocean uptake of atmospheric CO2 is about 2.61 GtC per year, w .A^370^A set of property distribution maps and property-property plots on eighteen potential density surfaces that cover th /e depth range of the North and Tropical Atlantic Ocean are presented using the data from the Transient Tracers in the Ocea 0n (TTO) cruises, Meteor Cruise 56 leg 5, Atlantic II cruise 109 legs 1 and 3, and the GEOSECS Atlantic Study. The properti 1es studied are salinity, oxygen, apparent oxygen utilization (A.O.U.), nitrate and silica. The results are discussed in te 2rms of the large scale oceanic circulation and mixing, and the nutrient dynamics. The Atlantic Ocean can be understood to 3consist of four layers, (1) the thermocline where there is a strong contrast between the oxygen-rich subtropical gyre wher 4e patterns supporting the ventilated thermocline hypothesis and be observed and the nutrient-rich equatorial ocean, (2) th 5e stagnant layer below (1) that features the Mediterranean Outflow, (3) the North Atlantic Deep Water layer which appears 6to be better ventilated than the layer above with a strong signal of the deep western boundary current, and (4) the bottom 7 layer with the influence of the Antarctic Bottom Water. The Mediterranean Outflow appears capable of driving strong salt 8fingering over a wide area in the subtropical Atlantic, which may drive strong isopycnal flows. The deep western boundary 9current shows irregularities which may be interpreted as stagnation points, and is seen to separate eastward along the equ :ator. The Antarctic Bottom Water that enters the northern western basin seems to upwell in a concentrated manner at about ;25 degrees N. Property-property plots are used to infer (1) a possibly significant cross-isopycnal mixing activity in the low Water into the deep western basin prior to TTO and consequent freshening of the deep Labrador and Irminger Seas in the past decade.ing is included. Also, it is concluded that the zero-feedback climate system includes the processes of radia @205^1^Prior,Stephen Arthur^1986^6^Field Studies of the Water Relations and Growth Response of Soybean (_Glycine max_ (L.) AMerr. 'Bragg') Grown under Different Water Regimes in CO{-2}-Enriched Atmospheres^M.S.^North Carolina State University^173 B^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^373^^^^^^^^^^^^Crop Science^Patterson, Robert P.^Rogers, Hugo H.^DE-AI01-81ER60001ichael","Atmospheric Sciences","Schlesinger, Michael","National Science Foundation grant ATM-9001310","" "Ramank DA^372^Soybean plants were grown from seeds in pots in open top field chambers under five CO{-2} concentrations (349 to 946 E LL{+-1}) and two water regimes. Differential watering was imposed after the seedling harvest (third node stage) and at t Fhis harvest CO{-2} enrichment had little effect on measured parameters. Harvests during reproductive growth [anthesis (T1) G and late pod fill (T2)] showed that water stress inhibited growth, but, the relative increase in total branch length and Hnumber, leaf area and dry weight in response to elevated CO{-2} were greater under water-stressed (WS) conditions than und Ier well-watered (WW) conditions. Water-stressed plants grown under 946 LL{+-1} CO{-2} had a total dry matter production g Jreater than WW plants at 349 LL{+-1} CO{-2}. Reproductive yield increases were represented by increases in seed number es Kpecially under WS conditions. However, weight per seed decreased with increasing CO{-2} level, thus the increase in total Lseed dry weight was not great. A phosphorus deficiency appeared to be restricting the seed response to elevated CO{-2}. Th Me mean relative growth rate (RGR) and mean net assimilation rate (NAR) increased with CO{-2} enrichment in the first inter Nval (day 5 to 2 weeks after emergence) and diminished with time thereafter at each CO{-2} level. At the second interval (2 O to 9 weeks), the direct effect of NAR was offset by lower leaf area ratio (LAR), however, since the LAR was greater for W PS plants the response of RGR to CO{-2} was somewhat similar under both water treatments. At the third interval (9 to 14 we Qeks), the RGR for WS plants remained constant across CO{-2} treatments, whereas under WW conditions a constant response of R NAR coupled with a negative response of LAR resulted in decrease in RGR under CO{-2}-enriched conditions. The decrease in S LAR was attributed to a decrease in specific leaf area while leaf weight ratio was unaffected by CO{-2}. Soil water deple Ttion rates decreased at the high CO{-2} levels by anthesis and early pod formation for (WW) and (WS) treatments, respectiv Uely. Subsequently, plants grown under high CO{-2} required fewer irrigations. At (T1) and (T2), water use per plant either V remained constant (WS plants at T1) or declined (WW plants and T1; WW and WS plants at T2) under CO{-2} enrichment despit We an increase in leaf area. Leaf stomatal resistance increased with CO{-2} enrichment at T1, however under WS conditions t Xhis was apparently offset by greater leaf area, thus accounting for the constant rate of water use. At T2, CO{-2}-enriched Y plants generally had higher leaf resistance, except at the end of the stress cycle where low CO{-2} grown plants exhibite Zd a sharp increase in resistance. The xylem potential (XP) at T1 and T2 was lowered by stress. The XP for WS plants at T2 increased with increasing CO{-2} concentration. the concentrations of cloud condensation nuclei (CCN) on which cloud drop \206^1^Mitchell,Connee S^1985^6^The Use of Climate Classification Schemes to Assess the Performance of General Circulation ]Models^M.S.^Oregon State University^145^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^375^^^^^^^^^^^^Atmospheric Sciences^Schlesinger, Michael^Gates, W. Lawrence^DE-AI02-93ER61589on grants ATM-8001702 and ATM-8205992dicts the concentrations _A^374^Two climate classification schemes, W. Kppen's and C. W. Thornthwaite's, were used to analyze the performance of th `e OSU AGCM in simulating both the present climate (model verification) and the climatic change induced by an increase in t ahe atmospheric CO{-2} (Sensitivity study). Climate classification maps were generated for each of the two schemes based on b the observed data of Crutcher and Meserve (1970), Taljaard et al. (1969), and Jaeger (1976), as well as for each set of m codel simulation data. Both Kppen's and Thornthwaite's schemes showed that the model did well in simulating the observed c dlimate, but no significant change in climate types was detected by either scheme for a quadrupling of atmospheric CO{-2} i en the OSU AGCM with seasonally-varying insolation and prescribed sea-surface temperatures. Thornthwaite's scheme also dete fcted no significant change in climate types in the OSU AGCM with annual-averaged insolation and a swamp ocean for a doubli gng of CO{-2}. The interannual variability of the simulated climate types was also investigated. It was determined that the h climate based on one year of model simulation data should not be taken as representative of the model climate because of ithe level of noise and the differing extents and intensities of the climate regions between simulation years. The climate jclassification schemes provide a different view of the GCM results by combining the raw data from the model to yield a des kcription of the change in terms of what type of vegetation could be supported. They also have the potential for detecting lclimate change in GCM experiments, although the method for determining the significance of such changes needs to be developed.ed to differences in ambient concentrations of CCN that cause variations in turbulent mixing in the marine boundary l n207^1^Jiang,Xingjian^1986^6^Role of Oceanic Heat Transport Processes in CO{-2}-induced Warming: Analysis of Simulations by o the OSU Coupled Atmosphere-Ocean General Circulation Model^M.S.^Oregon State University^154^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^377^^^^^^^^^^^^Atmospheric Sciences^Schlesinger, Michael^Gates, W. Lawrence^DE-AI02-93ER61589on grant AGth six latitudinal zones is developed to follow the vertical penetration of bomb tracers in the ocean and to examine excha rA^376^The OSU global coupled atmosphere/ocean general circulation model (A/O GCM) has been used to simulate the present (1 sxCO{-2}) climate and to investigate a CO{-2}-induced (2xCO{-2}) climate change. Previous analysis of the 1xCO{-2} simulati ton showed distinct errors in the simulated sea surface temperature (SST) and sea ice which were attributed primarily to th ue atmospheric GCM (AGCM). Analysis of the 2xCO{-2} simulation showed that the CO{-2}-induced warming penetrated into the o vcean; this caused a delay in the equilibration of the climate system with an estimated e-folding time of 50-75 years. The wpresent study has two objectives. The principal objective is to answer the question: By what pathways and through which ph xysical processes does the simulated ocean general circulation produce the penetration of the CO{-2}-induced warming into t yhe ocean? The secondary objective is to evaluate the performance of the oceanic GCM (OGCM) in the 1xCO{-2} simulation. The z comparison of the simulated 1xCO{-2} internal oceanic fields with the corresponding observations shows that although they { are basically similar, there are distinct errors. Further analysis shows that these errors were generated by the OGCM dur |ing its spin up integration prior to its coupling with the AGCM. This study thus shows that it is not sufficient to compar }e the simulated SST with the observed SST to evaluate the performance of the OGCM. It is also necessary to compare the sim ~ulated internal oceanic quantities with the corresponding observed quantities. The global mean analysis of the CO{-2}-indu ced climate changes shows that the ocean gains heat at a rate of 3 W/m{+2} due to the CO{-2} doubling. This heat penetrate s downward into the ocean predominantly through the reduction in the convective overturning. The zonal mean analysis shows that the surface warming increased from the tropics toward the midlatitudes of both hemispheres and penetrated gradually to the deeper ocean. The oceanic warming penetrated to a greater depth in the subtropics and mid-latitudes than in the equ atorial region. A zonal mean heat budget analysis shows that the CO{-2}-induced warming of the ocean occurs predominantly through the downward transport of heat, with the meridional heat flux being only of secondary importance. In the tropics t he penetration of the CO{-2}-induced heating is minimized by the upwelling of cold water. In the subtropics the heating is transported downward more readily by the downwelling existing there. In the high latitudes the suppressed convection plays the dominant role in the downward penetration of the CO{-2}-induced heating.t can be manipulated and then the net resul fficiencies^M.S.^Oregon State University^106^Thesis^^^Marine Transport^^^^^^^381^^^^^^^^^^^^College of Oceanic and Atmospheric Sciences^Sherr, Barry F.^Sherr, Barry F.^DE-FG06-92ER61423^rum, without addition of G. monosporum), four levels of b A^380^Protists have a key role in pelagic systems, both as the main bacterivores and major nutrient regenerators. Thus, kn owledge of protistan bacterivory rates and nutrient regeneration efficiencies is essential for studies concerning the stru cture and function of pelagic food webs. Current methods for the estimation of protistan bacterivory have methodological a rtifacts, especially when applied to open ocean communities. Also, measurements of regeneration rates for pelagic protists have been mainly limited to organisms in culture. Therefore, new methods should be developed for the measurement of proti stan bacterivory and nutrient regeneration rates. I developed a method for simultaneous estimation of protistan bacterivor y and regeneration efficiencies, based on a new approach for the study of microbial communities: the product release assay s (PRAs). PRAs estimate grazing rates from the rate of excretion of labeled products resulting from the digestion of added pre-labeled prey. The product regeneration efficiency, which is assumed to be constant, can also be estimated as an index of trophic complexity in food webs origination with the prey of interest. I chose ammonium as the excretory product, sinc e nitrogen is a major structural component of bacterial cells and {+15}N, a stable isotope of nitrogen can be used as a tr acer. The problems associated with the use of {+15}NH{-4}{++} include the difficulty of extracting ammonium from seawater, as well as the requirement of reasonably large sample sizes for the isotopic analysis. These problems limited the use of method for open ocean samples. In those cases where bacterial and protists abundances were high, I was able to calculate g razing rates and regeneration efficiencies that agreed with previously published values. In two of the experiments, protis ts and bacterial abundances varied during the incubation period, violating the assumption required for the calculation of rates as a simple negative exponential model, i.e., grazing rates are constant. Deterministic computer models designed to calculate rates which used bacteria and protist numbers as variables estimated grazing rates and nitrogen regeneration eff iciencies in the range of previous reported values. The use of different tracers, as well as different prey types is recommended as the direction for future studies using the product release assay approach.total length of total length of fibro A^382^Land-surface parameterizations based on a statistical-dynamical approach have been suggested recently to improve the representation of the surface forcing from heterogeneous land in atmospheric models. With this approach, land-surface cha racteristics are prescribed by probability density functions (pdf's) rather than single "representative'' values as in "bi g-leaf'' parameterizations. Yet the use of many pdf's results in an increased computational burden and requires the comple x problem of representing covariances between pdf's to be addressed. In this study, a sensitivity analysis of a land-surfa ce parameterization for atmospheric modeling was performed to evaluate the surface parameters most important to the variab ility of surface heat fluxes. The Fourier Amplitude Sensitivity Test (FAST) used for this analysis determines the relative contribution of individual input parameters to the variance of energy fluxes resulting from a heterogeneous surface. By s imultaneously varying all parameters according to their individual probability density functions, the number of computatio ns needed is very much reduced by this technique. This analysis demonstrates that most of the variability of surface heat fluxes may be described by the distributions of relative stomatal conductance and surface roughness. Thus, the statistical-dynamical approach may be simplified by the use of only these two probability density functions.-order turbulence radiat 211^1^DeWitt,Craig A^1983^6^Soil Moisture Stress and Nitrogen Fixation in Soybeans^M.S.^Clemson University^70^Thesis^^^Car bon, Climate, and Vegetation^^^^^^^385^^^^^^^^^^^^Agricultural Engineering^Lambert, Jerry R.^Acock, Basil^DE-AI01-81ER6000 A^384^Symbiotic nitrogen fixation in legumes is an economically important source of biological nitrogen in the food chain. The rate of nitrogen fixation in soybean (_Glycine max_ [L.] Merr. 'Bragg') is influenced by many environmental factors i ncluding soil water potential. This study was conducted to determine the effects of soil moisture stress on nitrogen[C{-2} H{-2}]-fixation in soybeans during early flowering. Nitrogen[C{-2}H{-2}]-fixation is a method of determining nitrogen fixa tion using the reduction of acetylene (C{-2}H{-2}) to ethylene in a surrogate reaction utilizing the nitrogenase enzymes. Soybeans were grown in a Norfolk sandy loam topsoil at 27/15 C (day/night) in a controlled environment in Soil-Plant-Atmos phere-Research (SPAR) units which were modified to permit in situ nitrogen[C{-2}H{-2}]-fixation measurements. At early flo wering, three water stress treatments (wet soil, 0-50 kPa, and 0-100 Kpa) were imposed for a minimum of three consecutive dry-down/recovery cycles. Nitrogen[C{-2}H{-2}]-fixation in soybeans during early bloom decreased during the first dry-down cycle in each treatment. Nitrogen[C{-2}H{-2}]-fixation increased upon rewetting in all treatments but not to pretreatment levels. Correlation coefficients of 0.63 and 0.58 were obtained for the first drydown in the dry and medium treatments, r espectively. No significant correlation was found for any treatment after the first dry-down period. Pod dry weight and po d nitrogen contents at harvest were unaffected by any of the soil moisture treatments in this experiment. Total plant dry weight at harvest was 25% lower in the 0-100 kPa treatment. The acetylene/ethylene system used in the determination of nit rogen [C{-2}H{-2}]-fixation proved to be nontoxic to the plants when sampled at 3-h intervals. This system in conjunction with SPAR units allowed semi-continuous measurements of nitrogen[C{-2}H{-2}]-fixation and its response to water stress in soybeans.nanometer liquid spheres, and a Monte Carlo code was developed in order to find the minimal energy configuration1system. Energies were computed using Lifshitz theory between macroscopic spheres. A simulation was performed for a speci A^386^The impact of subgrid-scale variability of land characteristics on land-surface energy fluxes simulated in atmospher ic models (e.g., GCMs) was investigated with Patchy Land-Atmosphere Interactive Dynamics (PLAID), a land-surface scheme de veloped by Avissar and Pielke (1989), which represents the land surface as a mosaic of patches. Eleven different distribut ions of the five predominant characteristics of land-surface schemes (i.e., stomatal conductance, soil-surface wetness, le af area index, surface roughness, and albedo) were considered. A total of 5,580,900 steady-state simulations was produced to analyze thoroughly this impact under a broad range of atmospheric conditions. We found that the more skewed is the dist ribution within the range of land-surface characteristics that is related nonlinearly to the energy fluxes, the largest wa s the difference between the energy fluxes calculated with the distribution and the corresponding mean. Among the various distributions considered in our study, the lognormal distribution produced the largest such difference, and negatively ske wed beta distributions resulted in negligible difference. In general, the latent heat flux was the most sensitive to spati al variability and the radiative flux emitted by the surface was the least sensitive. Our results indicate that it is very important to consider the spatial variability of leaf area index, stomatal conductance, and, in bare land, soil-surface w etness. The spatial variability of surface roughness is mostly important under neutral and stable atmospheric conditions. It appears that the relationship between albedo and surface energy fluxes is almost linear and, therefore, using a mean va lue of this characteristic is appropriate. This analysis emphasizes the need to develop land-surface schemes able to accou nt for spatial variability in atmospheric models, as well as the necessity to provide higher statistical moments when creating data sets of land-surface characteristics.han by gas chromatography or spectroscopy. Measurements from Greenland ice A^388^For the purpose of improving the parameterization of the planetary boundary layer (PBL) in atmospheric models, large -eddy simulations (LES) were used to study the statistical properties and the structure of turbulence in the PBL that deve lops in complex terrain. The impact of hill height, hill length, surface heat flux, atmospheric stability, and background wind were considered. As compared to a flat domain, a 400-m-high (40%-slope) hill starts to exhibit noticeable influence o n the different moments of most atmospheric variables, with a more pronounced impact on the higher moments. Wind speed, hi ll length, and surface heat flux all have at least some impact on the convective boundary layer (CBL). In particular, the structure and preferential location of the eddies is strongly affected by these parameters. A hill as small as 100 m high induces hill-valley circulations, which, however, are eliminated with a background wind as low as 2.5 m/s. This LES study indicates that only in very irregular terrain, with slopes larger than 20%, the current CBL parameterizations of microscal e turbulent fluxes need to be improved to represent correctly the atmospheric fluxes. Typically, such terrain is only foun d in mountainous regions. Since the mean surface sensible heat flux is the major surface forcing source for the CBL, the " mosaic-of-tiles" type of surface parameterization suggested by Avissar and Pielke seems appropriate for most continental areas.,"Turbulence in complex terrains,Large-eddy simulations,Parameterization of the planetary boundary layerlts could h .D.^State University of New York at Stony Brook^241^Thesis^^^Oceans^^^^^^^391^^^^^^^^^^^^Marine Science^Falkowski, Paul G.^Falkowski, Paul G.^DE-AC02-76CH00016^,"Wohlpart, A.","DE-AC05-76OR00033","Education" "Dean, Caryn Lyn","1993","Interact A^390^Laboratory experiments carried out with the diatoms _Chaetoceros muelleri_ and _Thalassiosira aestivalis_ showed tha t diatoms responded to changes in irradiance by changing their cellular concentration of diadinoxanthin (DD) and diatoxant hin (DT) via the diatoxanthin cycle. Those changes in pigmentation were accompanied by changes in fluorescence yield. Furt her experiments showed that light-induced diatoxanthin accumulation occurred on the same time scale as increases in the es timate for the rate for thermal de-excitation in the antenna of PSII. Reaction center fluorescence quenching was also evid ent from those experiments. Further evidence for involvement of the diatoxanthin cycle in energy dissipation was obtained from experiments with _Phaeodactylum tricornutum_ and field samples. It was determined that dithiothreitol (DTT) inhibits the diadinoxanthin de-epoxidase. DTT inhibited DT accumulation as well as increases in DT accumulation resulting from de n ovo pigment synthesis had the same effect on fluorescence quenching. A large fraction of fluorescence quenching was found to occur independently of DT-cycling and was associated with dissipation processes occurring at the reaction center. Altho ugh the DT-cycle was associated with increases in energy dissipation, no evidence of photoprotection was found from measur ements of photochemical efficiency or of reaction center protein. Nutrient stress (N, P, or Fe) was found to induce accumu lation of DD and DT in _P. tricornutum_. The dependency of quenching coefficients on DT accumulation changed according to the specific nutrient stress and the degree of starvation, estimated from Fv/Fm. The results were interpreted in view of s tructural changes in PSII known to occur under nutrient stress. Field investigations of DT-cycling in Auke Bay, Alaska, sh owed that light induced changes in DT and DD concentration may be used to estimate vertical advection under certain circum stances, but that other factors besides irradiance may affect the cycle. Although it was attempted to measure DT concentra tions in the subtropical Pacific ocean it was not possible. The time needed for sample preparation was found to be too lon g. However, phytoplankton pigment markers were used to estimate changes in the phytoplankton population produced by a wind-induced mesoscale eddy.lts were very similar, with an inversion height near 960 mb. Therefore, the model is thought to b 215^1^Mummey,Daniel Lynn^1993^6^Nitrous Oxide Emissions from a Shrub-Steppe Ecosystem: Sources, Regulation and Spatial and Temporal Variability^M.S.^Washington State University^62^Thesis^^^Ecosystems Function and Response^^^^^^^393^^^^^^^^^^^^Crops and Soils^Smith, Jeffrey L.^Rogers, Lee E., and Harvey Bolton, Jr.^10562/21428h.D.","University of California at Ber A^392^The first study was designed to examine the sources and regulation of N{-2}O flux from an undisturbed shrub-steppe e cosystem. The second study was designed to determine how the factors which regulate N{-2}O flux interact in the field to i nfluence spatial patterns and temporal variability. Our results showed that nitrification is the dominant source of N{-2}O in this ecosystem. Nitrous oxide flux is regulated by interactions between soil moisture content and N availability. Nitr ous oxide flux was found to be largely spatially dependent at the scale of this study. The variability of N{-2}O flux that could be accounted for by spatial dependence and the spatial association with vegetation increased with soil water conten t. Pulses of N{-2}O and N-mineralization occur after wetting of dry surface soil that are strongly correlated with plant a ssociated soil. Approximately 21% of the annual N{-2}O flux from this ecosystem can be attributed to periods within 48 hours after precipitation events.k of predicting the responses of forest to climate change. The substantial scientific uncer5A^468^Due to global climate change, predictions are that night temperatures will become warmer than present, but day tempe 216^1^Leadley,Paul W^1985^6^Effects of Air Quality on Soybeans: (1) Effect of CO{-2} on Leaf Area Development and (2) Effe ct of O{-3} on Canopy Light Interception and Crop Growth Rate^M.S.^North Carolina State University^129^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^396^^^^^^^^^^^^Botany^Reynolds, James F.^Reynolds, James F.^DE-AI01-81ER60012l have to procee A^395^The effects of air quality factors on soybean were studied using open-top field fumigation chambers. The study consi sted of two parts: (1) the effects of elevated CO{-2} on mainstem leaf area development and relationships between leaflet length, width, area and dry weight in _Glycine max_ (L.) Merr. 'Bragg' and (2) the effects of ozone on light interception,  conversion of light energy into shoot biomass and interaction with water stress in _Glycine max_ (L.) Merr. 'Davis". (1) Effects of CO{-2} on soybeans were studied using three CO{-2} concentrations: 349, 502 and 645 ppm. Analysis of mainstem c entral leaflet growth indicated that the first leaflet grew faster and the second leaflet appeared earlier in elevated CO{ -2} atmospheres. The rate of expansion, duration of expansion, rate of appearance and final area of subsequent leaflets we re unaffected by CO{-2}. Analysis of non-destructive estimates of leaf area and dry weight indicated that leaflet length t imes width was an excellent predictor of central leaflet area and trifoliolate area, and trifoliolate dry weight could be adequately predicted from leaf area if a linear model with CO{-2} concentration was incorporated. (2) There were five ozon e treatments in the ozone study, ranging from 25 ppb to 100 ppb and two watering treatments providing water-stressed and n on-stressed conditions. The effects of O{-3} were examined using light conversion analysis which resolves crop yield into the product of canopy light interception, fractional allocation of biomass to seed and the efficiency of conversion of lig ht energy into biomass. Analysis of the non-stressed soybean growth indicated that high ozone levels reduced seed yield by  decreasing the efficiency of conversion of intercepted light to biomass. Canopy light interception and fractional allocat ion were not affected by CO{-2}. Comparison of results with an earlier study by Unsworth _et al._ (1984) suggests that uti lization efficiency consistently decreases with ozone dose. Large differences in utilization efficiencies between the two studies were attributed to different light environments and water stress caused by an unusually hot and dry year. Analysis  of the growth of water-stressed soybeans indicated that water stress reduces yield by reducing utilization efficiency and  the fraction of incident light intercepted by the canopy. A modified light conversion model was used, which incorporated a dry weight loss term. Results from the application of this model indicated that ozone protected soybeans from water stress, but water stress did not keep ozone from reducing light conversion efficiencies.sition fluxes. Airborne concentration ultural sites had lower soil carbon contents than those in the mature forests. The magnitude of the differences between th e cultivated sites and the mature forests varied by life zone, and ranged from 50% in the wet forest life zone to 75% in t he dry ones. Pasture sites had levels of soil carbon comparable to those of the mature forests (71.0-111.7 t/ha, 0-50 cm d eep). The soil carbon content of secondary forests was progressively higher in progressively older stands. By approximatel y 30-40 yr, the soil carbon content of secondary forests was similar to that of mature forests in both wet and dry life zo nes. Conversion of forests to permanent cultivation results in a net release of carbon to the atmosphere. However, the inc rease in soil carbon in pasture and through forest succession may off-set this loss to an extent, but ultimately more carbon will be lost of the atmosphere than is being stored by the soil in the tropics due to deforestation.e vegetation depos 218^1^Leavitt,Steven Warren^1982^6^Inference of Past Atmospheric {+13}C and P{-CO2} from {+13}C/{+12}C Measurements in Tr !ee Rings^Ph.D.^University of Arizona^221^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^400^^^^^^^^^^^^Geosciences^Long, Austin^Long, Austin^DE-AC02-81EV10687. Uncertainty in predictions of deposition models should be recognized as origi #A^399^Carbon dioxide releases from fossil-fuel burning is significant enough that we may soon experience perceptible chang $es in climate with important human consequences. Man's activities involving deforestation and agriculture have undoubtedly % also affected atmospheric CO{-2}, although quantitative, and even qualitative, net effects of these processes are incompl &etely understood relative to fossil-fuel production. An accurate reconstruction of past {+13}C/{+12}C ratios of atmospheri 'c CO{-2} may provide key constraints on the historical activity of the biosphere as CO{-2} source or sink. Tree rings appe (ar to be a repository of this information but there is much noise in the collection of previous reconstructions, presumabl )y associated with site selection, radial variability, choice of representative wood chemical constituents, and subtle effe *cts of climate and fractionation. This study attempts to avoid these pitfalls and develop a 50-yr {+13}C{-ATM} record fro +m juniper trees (genus _Juniperus_), in fact, by taking advantage of the influence of climate on fractionation. Trees were , harvested from suitable sites in close proximity to weather stations with monthly records of temperature and precipitatio -n. Ring material was then separated from each of the sections in 5-yr intervals from 1930 to 1979 around their full circum .ference, and cellulose was extracted from the wood. After measuring {+13}C of the cellulose by standard mass-spectrometri /c techniques, a variety of {+13}C vs. climate functions were examined for each interval. The most useful relationships fo 0r at most 7 of the 10 sites were {+13}C with December temperature or precipitation, because the coefficients were nearly 1constant from one interval to the next (averaging -0.27{+}/{-} C{+-1} for temperature and -0.04{+}/{-} mm{+-1} for 2precipitation) and the intercepts differed. Local pollution effects are believed responsible for the three anomalous sites 3. The separation of these regression lines of different intervals is interpreted as the response of trees to the changing 4{+13}C of atmospheric CO{-2} so that {+13}C{-ATM} curves are constructed from this spacing. The shape of the best-fit re 5construction suggests the biosphere has acted as CO{-2} source to about 1965 and may now be a net sink. Although these con 6clusions are limited by certain assumptions and statistical restrictions, evidence from the recent scientific literature tends to support the increasing role of the biosphere as an important carbon sink.7x105 molec/cm350%.","","Wofsy, Stev 8; and tests for the detection of periodicities using the power spectrum method of Jenkins and Watts (1968). In addition, a 9 gaussian low-pass filter was applied to each series as well as identifying extreme wet and dry seasons over the course of : each record. The secular variability of seasonal precipitation is discussed for each region with reference to the prevail ;ing mode of atmospheric circulation. Interregional comparisons, on a seasonal and annual basis, were also accomplished. Pe , was noted in every region, including the Northern Hemisphere, except China. Over the Northern Hemisphere continental are ?as, taken as an aggregate, precipitation probabilities are seen to be rising since the late 1920's-early 1930's in every s @eason. Persistence for the standard seasons was essentially nonexistent, but, the annual spectrum noted positive autocorre Alations from lags one to five being significant at lag five. Periodicities, as with the regional series, were in the 2-5 year range, in addition to a near 13 year cycle in the summer spectrum.a low carbon future with as little loss of output a CA^246^The global carbon cycle is analyzed from the point of view of the distribution and exchange between the reservoirs o Df atmosphere, biosphere, and oceans. The partition of excess CO{-2} between the atmosphere and the oceans, introduced in t Ehe atmosphere as a perturbation over a previous steady state reached by the atmosphere-ocean system, is examined with a bo Fx-diffusion model. This model considers vertical diffusion below the mixed layer and also isopycnal diffusion from the col Gd parts of the ocean surface as the mechanisms that control the removal of the perturbation from the mixed layer into the Hdeep sea. The calibration of the ocean model is made by inspecting the predicted distribution of natural carbon-14 and bom Ib carbon-14 and Tritium. As a global average the model reproduces the basic patterns of the distribution of these tracers. J For a perturbation source that grows exponentially at the same rate as the industrial releases of CO{-2} in the last few Kdecades it is calculated that a little over 50% of the excess CO{-2} would remain in the atmosphere. This result suggests Lthat no significant net source or sink, besides the industrial perturbation and ocean up-take, are involved in the evoluti Mon of the CO{-2} atmospheric concentration for the last few decades. The atmospheric distribution is investigated using a Nbox model for latitudinal belts of 10 degrees. The mixing inside the atmosphere is parameterized by a constant meridional Oeddy diffusivity with a restriction in the exchange across the ITCZ. The ITCZ is assumed to move with the seasons between P10N and 10S. The atmospheric model is calibrated by the consideration of the distribution of some halocarbons, excess ca Qrbon-14 from the nuclear tests and strong gradients in the CO{-2} concentration across the ITCZ. The considered values for R the meridional eddy diffusivity is 31 x 10{+10} cm/sec and the exchange across the ITCZ is decreased by a Restriction F Sactor of 0.1. The exchange with the oceans is taken as proportional to the difference in partial pressure of CO{-2} in the T atmosphere and in the surface of the ocean. The distribution of the ocean surface pCO{-2} is based on GEOSECS data. The e Uxchange with the biosphere is divided into two components, the seasonal variations in the balance between the uptake and r Velease of carbon and local secular variations in the biomass. The seasonal component is modeled as proportional to the net W primary productivity in each latitudinal belt coupled with a scheme that describes the variations in the uptake and relea Xse of carbon. The basic structure of the latitudinal variation in the amplitude of the seasonal oscillation is approximate Yly reproduced. The local secular variations in the land biomass is treated as a residual component in the atmospheric mode Zl. To reproduce the trends in the observed evolution of concentration for the last two decades a scenario is proposed that [ involves a recovery in the biomass in northern temperate zone and a decrease in equatorial and southern latitudes. The pr \oposed scenario assumes an overall balance between the northern sink and southern source, both with a magnitude of about 1 x 10{+15} gC/y.ose depicted in trajectory maps, are much more robust, maintaining a high level of accuracy for periods o ^219^1^Detwiler,Ralph Paul^1986^6^Tropical Forests and the Global Carbon Cycle^Ph.D.^Cornell University^415^Thesis^^^Carbon _, Climate, and Vegetation^^^^^^^405^^^^^^^^^^^^Ecology and Systematics^Hall, Charles A.S.^Hall, Charles A.S.^DE-AC05-84OR214006ation studies, both for the determination of instrument accuracy and precision. Third, trajectory mapping was used t aA^404^The concentration of carbon dioxide in the atmosphere has increased from 280 parts per million circa 1750 to 345 par bts per million in 1984. One cause of this increase, and the principal one in recent years, has been the combustion of foss cil fuels. Another has been the destruction of forests and their replacement with agro-ecosystems, whose vegetation and soi dl contain much less carbon than the vegetation and soil of undisturbed forests. In the past, the destruction of temperate eforests may have contributed significantly to the increase in atmospheric CO{-2}. It now appears, however, that the cleari fng of tropical forests is the major source of CO{-2} from terrestrial ecosystem. Tropical forests are cleared for shifting g cultivation, permanent agriculture, pasture, and timber. These land uses differ as to the amount of carbon stored in thei hr vegetation and soil. To calculate the net release of CO{-2} from tropical forest clearing, one must determine: (1) the r iates at which tropical forests are cleared for these various uses and the rate at which cleared areas are abandoned in shi jfting cultivation; (2) the carbon stored in the vegetation and soil of primary forests, logged forests, secondary forests, k agricultural fields and pastures; and (3) the fate of carbon contained in cleared vegetation and soil. These date are use ld in computer model that simulates land use change in the tropics and its effects on vegetation and soil and calculates th me net flux of CO{-2} between tropical ecosystems and the atmosphere. The model is useful because it permits testing the se nnsitivity of the calculated flux to uncertainties in the estimates of land use change, carbon storage, and the fate of cle oared vegetation. The model has been used to calculate the net release in 1980 from the vegetation of four Latin American c pountries and from the vegetation and soil of the entire tropics. This research indicates that land use change in the tropi qcs released at least 0.4 x 10{+15}g but not more than 1.9 x 10{+15}g of carbon in 1980, with the more likely range being 0 r.4-1.6 x 10{+15}g. Decreases in soil organic matter were responsible for 0.1-0.3 x 10{+15}g of the release, while the burning and decay of cleared vegetation accounted for 0.3-1.6 x 10{+15}g. of soil moisture and damage. The vertical restructu t220^1^Arnosti,Carol^1983^6^Structural Characterization and Bacterial Degradation of Marine Carbohydrates^Ph.D.^Massachuset uts Institute of Technology and Woods Hole Oceanographic Institution^239^Thesis^^^Marine Transport^^^^^^^407^^^^^^^^^^^^Joint Program in Oceanography^Repeta, Daniel J.^Repeta, Daniel J., and Timothy I. Eglinton^DE-FG02-92ER61428s model is used wA^406^The goal of this thesis was to develop and apply an integrated chemical and microbial approach to study the effects xof chemical structure on the rates and patterns of carbohydrate degradation by anaerobic marine bacteria. Polysaccharides yproduced by five species of marine plankton, _Dunaliella tertiolecta_, _Emiliania huxleyi_, _Stephanopixis palmeri_, a _Ph zaeocystis_ sp., and _Synechococcus_ WH7335, were surveyed using one- and two-dimensional nuclear magnetic resonance spectr {oscopy (NMR). Two carbohydrates from _Synechococcus_ WH7335 were characterized in detail. _Synechococcus_ produced an (1, |4) glucose polysaccharide with (1,6) branches, which probably function as an energy reserve. The nominal molecular weight } of the polysaccharide was 5000 daltons. Large quantities of a glycerol-polysaccharide, which was tentatively identified ~as a teichoic acid similar in structure to teichoic acids found in cell walls of gram-positive bacteria, were also produce d by _Synechococcus_ WH7335. This is the first report of teichoic acids in cyanobacteria. Enrichment of bacteria from anox ic marine sediments on specific carbohydrate yielded reproducible model systems with which to study the degradation of che mically well-defined substrates. Headspace gases (CO{-2}, H{-2}, CH{-4}, H{-2}S) were monitored by gas chromatography, and carbohydrate substrates and intermediates were separated and quantified via gel-permeation chromatography and high-pressu re liquid chromatography. The transfer of carbon from substrates through to end products was followed quantitatively. Nucl ear magnetic resonance spectroscopy was used to check for selective structural alterations (such as preferential cleavage of specific linkage types or positions) of the substrates. A series of enrichment experiments showed that mixed cultures o f marine bacteria distinguish even between small, very closely-related substrates which do not require extracellular hydro lysis prior to uptake. A galactose-(1,3)-arabinose dimer was degraded at half the rate of seven other similar disaccharid es and three larger oligosaccharides. A further series of degradation experiments with polysaccharides (pullulan, laminari n) showed that they are degraded by bacteria at virtually the same rate as structurally related substrates in the molecula r weight range of 300-600 daltons. Degradation of the branched glucan and the teichoic acid-type polysaccharide from _Syne chococcus_ WH7335 was also very rapid. The time-course of bacterial hydrolysis of pullulan was examined with gel permeatio n chromatography and NMR to provide the first molecular-level evidence in marine systems of the bacterial extracellular tr ansformation of high molecular weight organic matter to lower molecular weight organic matter. NMR spectra provided eviden ce that the pullulan was hydrolyzed by pullulanase, an endo-acting extracellular enzyme which preferentially hydrolyzes ( 1,6) linkages. This is the first experimental evidence of pullulanase activity among marine mesophilic bacteria. The cultu re results suggest that enzymatic hydrolysis of macromolecular carbohydrates to transportable pieces is not the slow step in bacterial degradation of at least some types of polysaccharides. The results from the oligosaccharide experiments sugge st that certain heteropolysaccharides may not be degraded as quickly. Chemical structure can be more important than molecu lar weight in determining degradation rates of carbohydrates. Varying rates of organic polymer degradation in anoxic sediments may be largely determined by the sensitivity of bacterial enzymatic and transport systems to structural features.eopAnthony E.^DE-FC03-90ER61010^irectly experienced and for offering behavioral solutions to environmental problems. This st A^408^Physiological basis of heat injury during reproductive development was studied using contrasting cowpea (_Vigna ungu iculata_ L. Walp.) genotypes subjected to different night temperatures and light qualities under ambient and elevated leve ls of CO{-2} in growth chambers. The objectives were to: determine the stages of reproductive development when damage due to heat stress occurs; test whether specific tissues or developmental processes are damaged during the periods of sensitiv ity to heat; evaluate the interactive effects of temperature and light quality during the day on floral development; and t est for possible associations between carbohydrate limitations and sensitivity to heat during reproductive development. Hi gh night temperature during the vegetative and early reproductive states causes complete suppression of floral buds on the main stem. Transfer experiments demonstrated that plants were not sensitive to heat at a particular stage of development but that the duration of heat experience is critical for floral bud development. Two weeks or more of continuous or interr upted heat caused complete suppression of all floral buds suggesting that the heat stress effect was cumulative over time. The degree to which high night temperature suppressed floral bud development depended on the R/FR ratio during the day an d values of 1.3 to 1.6 were required to elicit the same responses as occur under natural sunlight. High night temperature during anther development causes male-sterility and results in no pod set due to low pollen viability and anther indehisce nce. The stage of floral development most sensitive to heat occurred nine to seven days before anthesis. During this perio d, premature degeneration of the tapetal tissue and lack of endothecial formation were detected in heat stressed plants. T hese two abnormalities may be responsible for the low pollen viability, low anther dehiscence and low pod set observed und er heat stress. Under high night temperature, different heat sensitive genotypes either produced no flowers or set no pods at either ambient or elevated CO{-2}, whereas the heat tolerant genotype abundantly set pods. The high pod set of the hea t tolerant genotype was associated with higher levels of sugars in peduncles compared with the heat sensitive genotypes. E levated CO{-2} resulted in higher overall carbohydrate levels in heat sensitive genotypes but sugar levels in peduncles we re not improved indicating that heat stress affects assimilate demand to a greater extent than assimilate supply. It is hy pothesized that sensitivity to heat during reproductive development is due to developmental lesions that are not overcome by enhanced carbohydrate supplies through CO{-2} enrichment. A heat tolerant genotype was most responsive to CO{-2} enrichment, with respect to pod production, under either high or intermediate temperatures.ata from portable automated mesonet . vertical control of water column flux balances and to determine the bottom source strength of various geochemical tracer s. Relative bottom and water column sources for the geochemical tracers are strongly correlated with lateral exchange. A s olution is found which constrains the lateral exchange rate to be about 150-200 years. The model predicts that 75% of the excess silica in the deep Bering Sea water column dissolves from the sediments, while 25% dissolves in situ. Including the sediment accumulation, only 15% of the particulate silica flux falling from below 1500 m dissolves in the water column. H alf the flux reaching the sediments is buried. The model predicts an upwelling rate of 2.8 m/yr in the deep basin with an inflow of 0.08 Sv at the sill, and a vertical mixing coefficient of 0.7 cm/sec. It is argued, however, that geothermal he ating and radiocarbon constraints on the absolute time scale apply only in the lower part of the water column where the fl Kushing by Pacific water is the critical factor. The importance of vertical mixing can only be assessed if the upwelling fl 223^1^Chen,Liqiang^1994^6^The Simulation of Reflection Function of Clouds Using the Adding-Doubling Method^M.S.^South Dako ta School of Mines and Technology^57^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^413^^^^^^^^^^^^Meteorology^Han, Qingyuan^Han, Qingyuan^DE-FC03-90ER61010^ consistent across the top of the surface layer. Wind shear A^412^Clouds reflect about 50% of the incident solar radiation and thus account for most of the planetary albedo. The inve stigation of energy reflected by clouds is very important to estimate the global climate change. The plane parallel assump tion is widely used in both model and remote sensing studies for calculating cloud reflections. The objective of this stud y is to use AVHRR data to test the plane parallel assumption. The AVHRR Channel 1 data is used, which has the wavelength o f 0.58m-0.68m. In order to test the plane parallel assumption, a radiative transfer model is used. The model considers o zone absorption and the atmospheric molecular scattering. There are three layers in the model, in which layer ozone absorp tion, the molecular scattering and Mie scattering are independently processed. The reflection function, defined as the rat io of the reflected radiance to the incident solar radiance, is used to describe the angular dependence of the reflected r adiation. The adding-doubling method is used to deal with multiple scattering. One month of the AVHRR data is averaged for different solar and satellite viewing zenith angles as well as relative azimuth angles in order to obtain an averaged ref lection function. The model results show that the reflection function depends on the cloud optical thickness. The comparis on between the model results and the AVHRR data shows that at larger solar zenith angle the plane parallel assumption caus es larger error. However, on average, cloud optical thickness derived from plane parallel assumption does not show significant bias.= 0.1*Zi (the depth of the mixed layer), but the relationship is weakly correlated. It is also found that the s 224^1^Ulman,James C^1994^6^Impact of Air Mass History on the Chemical, Microphysical, and Radiative Properties of Clouds a t Mount Mitchell, North Carolina^M.S.^North Carolina State University^115^Thesis^^^National Institute for Global Environme ntal Change (NIGEC)^^^^^^^415^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Saxena, Vinod K.^Saxena, Vinod K.^DE-FC03- A^414^Cloud water acidity and ionic content, as measured at the Mount Mitchell State Park observing site (35" 44'05" N, 82 " 17'15" W, 2038 m MSL -- highest peak in the eastern U.S.), using a passive cloud water collector, are directly influence d by the trajectories of cloud forming air masses which pass over areas of varying levels of pollutant emission. Regions o f the United States which are emitters of high levels of pollutants, such as SO{-x} and NOx, will thus serve to reduce obs erved pH levels in cloud water samples and raise the levels of acidifying ions, such as sulfate and nitrate. Cloud water i s one of the best indicators of pollution levels because all water soluble impurities in one cubic meter of air from an ai r mass are found condensed in typically one milliliter or less of the cloud water. The 48-hr backward trajectories for all 39 cloud events during the 1993 field season (15 May 1993 - 14 October 1993) were computed using the Hybrid Single-Partic le Lagrangian Integrated Trajectories (HY-SPLIT) model. Three sectors, identified as the polluted sector, from 290 to 65 azimuth relative to the site, the continental sector, 240 to 290 azimuth, and the marine sector, 65 to 240 azimuth, w ere used to classify the cloud forming air masses. The polluted sector was associated with the lowest overall pH averages, with the marine sector following closely behind. The highest average pH values were received from air masses indicated as having crossed the continental and the marine sectors (in combination), with the largest portions of those air mass traje ctories passing through the continental sector (exclusively continental sector air masses were also the most frequent). Th ese observations are in agreement with findings in Colorado where aerosols produced by wind erosion were responsible for neutralizing the precipitation acidity.l potential temperature and LCL are presented and evaluated. These distributions ar 225^1^Burns,Kerry Lee^1994^6^Cloud Microstructure, Acidity and Reflectivity: Case Studies and Implications for Regional Cl imate Change^M.S.^North Carolina State University^36^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^417^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Saxena, Vinod K.^Saxena, Vinod K.^DE-FC03-90ER61010mono-modal A^416^A sensitivity analysis was performed to determine the effect of small fluctuations in cloud microphysical parameters on the cloud albedo. It is discovered that unpolluted marine clouds should have a greater radiative response to changes i n cloud droplet spectra than more polluted continental clouds. It is further shown that increasing droplet concentration b y a few percent can have a greatly increased cloud albedo and produce a cooling effect on regional climate. In situ cloud measurements were taken during 39 individual cloud events between June and October 1993 in Mount Mitchell State Park, Nort h Carolina. Cloud droplet spectra were measured coincidentally with cloud water pH and chemical composition. A total of 11 3 hourly cases were recorded. Nine of these cases corresponded with satellite derived direct cloud albedo measurements. Sc atter graphs were generated showing how albedo varies with cloud droplet concentration, cloud droplet size, cloud liquid water content, cloud water pH, cloud thickness, and precursor cloud condensation nuclei concentration.0* Sciences" 226^1^Gaffin,Stuart Roger^1986^6^Variable Seafloor Spreading Rates and Global Sea-Level: Introducing a Ridge Volume Invers ion Technique^Ph.D.^New York University^122^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^419^^^^^^^^^^^^Applied Science^Hoffert, Martin I.^Hoffert, Martin I.^DE-FG02-85ER60350ral Circulation Model. The CO2 forcing is defined as the ini A^418^The basic quantitative distinction between global oceanic ridge volume and the global rate of seafloor generation is made fully explicit. From this, the question of inversion over time from the former quantity into the latter is then pose d using a generalized expression to approximate the global subduction zone distribution. Two numerical methods are describ ed. Then, assuming the hypothesis that long term (10{+8} yr) eustatic sea level change is due primarily to changing ridge volume, an inversion of a widely cited Phanerozoic sea level curve (Vail) is also presented. The approach taken here is ex pected to be of direct importance for quantitative models of the carbonate-silicate cycle which seek to develop scenarios for atmospheric carbon dioxide variations over geologic time scales. Indeed, the testing of sea level inversion, as performed here, may ultimately come from the degree of correspondence with past climate variation.rmer run. The clear sky CO2 f 227^1^Hsieh,Ching-Tzong^1985^6^Three Reservoir Models for Climate Evolution with a Two-Dimensional World Ocean^Ph.D.^New Y ork University^148^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^421^^^^^^^^^^^^Applied Science^Hoffert, Martin I.^Hoffert, Martin I.^DE-AC02-81EV10610cing through the depth of the troposphere is about 50% greater in the warmer run than A^420^A three-reservoir parameterized climate model is formulated from the principle of energy balance. The system, compos ed of the atmosphere, ocean and land, covers pole-to- pole regions. Land-sea distribution along the latitudinal direction is taken into consideration to simulate climatic response in both hemispheres. The ocean part includes the mixed layer and deep sea which has isopycnal structure. The model is designed to investigate the climatic responses to external and inter nal perturbations. External perturbations mainly refer to the seasonally varying solar radiation, whereas internal perturb ations to the change in CO{-2} concentration in the atmosphere. Seasonal responses to the seasonal variation of solar radi ation for present CO{-2} level are tested to calibrate parameters of the model. Long-term responses to the change of CO{-2 } level are also investigated. Steady-state and transient solutions are obtained to present pole-to-pole temperature field s. The model is coupled to the parameterized output of the LOWTRAN 5 longwave radiation code, which calculates outgoing an d downward longwave radiation. Steady-state solutions are obtained by specifying step changes of CO{-2} level to the syste m; transient solutions are obtained by specifying the time history of CO{-2}. Sensitivities to doubling CO{-2} and a 2% in crease of the solar constant of the present model are compared with GCM results. Zonally averaged temperatures at differen t latitudes are calculated. Temperature fields are obtained for air, water and land. The calculated seasonal temperature fields are compared with the observed data to test the performance of the model. and surface moisture flux. Three on 228^1^Volk,Tyler^1984^6^Multi-Property Modelling of the Marine Biosphere in Relation to Global Climate and Carbon Cycles^P h.D.^New York University^348^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^423^^^^^^^^^^^^Applied Science^Hoffert, Martin I.^Hoffert, Martin I.^DE-AC02-81EV10610llations in cumulus convection and latent heat release. In addition, the os A^422^A natural hierarchy of tracers based upon biological source-term complexity gives a systematic sequencing for a mode ling procedure, which should be generally applicable to different types of models that need multi-property outputs. The pr ocedure moves from dynamics to single-source tracers to double-source tracers. The surface water pCO{-2m} and temperature relationship is examined seasonally, geographically and biologically. A meridional diffusive model reproduces the observed 1-2% pCO{-2m} per degree C of the Atlantic gyres. Differences in the seasonal orbit of pCO{-2}/T potentially useful in fi eld studies result from varying the magnitude and seasonality of biological productivity. The multi-property procedure is used in a 1-D upwelling-diffusion model to produce simultaneous, globally-averaged profiles of temperature, phosphate, nit rate, oxygen, alkalinity, and total carbon dioxide. Depth-dependent source terms simulate the oxidation and dissolution pr ocesses. Traditional Redfield ratios coupling the organic source terms are adequate algorithmic proportionalities for the global profiles. Bottom and intermediate water formation is modeled both as a pipeline with parameterized fluxes of nutrie nts and as a buoyant plume that entrains water during descent. The model transfers O{-2} and CO{-2} between the surface mi xed layer and the polar sea. The relative strengths of biology and dynamics as pumps that affect pCO{-2atm} by creating su rface-to-deep CO{-2} concentration differences are calculated. A full dynamic pump and no biology produces a pCO{-2} value  of 460 ppmv. Also eliminating the dynamic pump by lowering the degree of polar pCO{-2} equilibrium raises pCO{-2atm} to 7 20 ppmv. The model's usefulness in coupled multi-property transients is demonstrated by switching off biology and followin g all tracers toward their abiotic distributions. The mathematics of a 2-D isopycnal mixing model is presented. Along-and- across isopycnal diffusivities are rotated to horizontal-and-vertical diffusivities. Along with thermohaline circulation, equatorial upwelling represents a wind-driven circulation. The necessity for incorporating bottom water plumes and intermediate water is concluded from the 1-D modelling procedure.er model using the suite of seven test cases proposed by Willia90ER61010^erformance characteristics are presented. The test cases show that the evolution of the fields is independent o 229^1^Lu,Cheng-Hsuan^1992^6^Interaction of Coherent Structures with the Forest Canopy^M.S.^State University of New York at  Albany^109^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^425^^^^^^^^^^^^Atmospheric Sciences Research Center^Fitzjarrald, David R.^Fitzjarrald, David R.^DE-FC03-90ER61010","Randall, David A.","Atmospheric Science", A^424^Turbulence measurements obtained from instruments mounted on towers in a deciduous forest in central Massachusetts a re analyzed to understand the statistical characteristics of coherent structures and how are these structures influenced b y the biomass structure. A new technique, wavelet transforms, is used to study these time series data. This technique is r ecommended for detection of irregular patterns which are intermittent and contain sharp local gradients. Different wavelet ! functions are used and their results compared. The mean duration of events that contribute most to signal variance and tu "rbulent fluxes are estimated by computing the wavelet spectra. The fraction of momentum and heat transport contributed by #coherent structures are calculated over longer time periods by this objective detection method. A smaller fraction of tran $sport contributed by the coherent structures suggests that previous studies based on idealized data sets may overestimate %their importance. Composited flow pattern and flux structure associated with the coherent structures are displayed. Above &the forest canopy, the coherent structures are characterized by ramp-downdraft pattern with twin peaks of fluxes surroundi 'ng the temperature microfront. Below the forest canopy, the horizontal wind leads the air flow aloft in the summer and win (ter periods, but the phase of temperature fluctuations related to the microfront are different during different seasons. T )his illustrates the air flow in the trunk space is influenced by the local environment (in-canopy stability for temperatur *e fluctuation and surface pressure field for horizontal wind component) most of the time. Intermittently, strong gusts can + transport the air far above the canopy and zero-gradient or counter-gradient fluxes are observed. Combined the filtering ,effect of forest canopy and the statistical characteristics of coherent structures, it is suggested that one can construct a parameterization model to simulate the atmosphere-forest interaction.,"Randall, David A.","Atmospheric Science","Randa .230^1^Sakai,Ricardo^1994^6^Leaf Area Influence on Turbulent Exchange in a Deciduous Forest^M.S.^State University of New Yo /rk at Albany^128^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^427^^^^^^^^^^^^Atmospheric Sciences Research Center^Fitzjarrald, David R.^Fitzjarrald, David R.^DE-FC03-90ER61010 which limit the production of carbon d 1A^426^A study over a deciduous forest has been performed to the examine the role of the leaves in the forest-atmosphere in 2teraction. Due to the seasonal presence of leaves, a deciduous forest is a good 'laboratory' to study this interaction. Th 3is study has two major parts. The first is concerned with the measurement of LAI (Leaf Area Index) using digital image pro 4cessing. The second examines the effects of the leaves during the year and the impact of their presence on transition seas 5ons (spring and autumn) during two study years. Comparison with satellite measurements is performed to use these relations 6hips in models that require vegetation-atmosphere parameterizations such as GCMs, or mesoscale models. Even though digital 7 images captured the transition from a leafless canopy to a foliated canopy and vice-versa, the digital images used in thi 8s study led to low estimates of LAI and PAI (Plant Area Index). Linear adjustments using LAI and PAI from direct measureme 9nts a PAR (Photosynthetically Active Radiation) due to absorption of visible light in the canopy. Water vapor concentratio :n increases and the CO{-2} concentration decreases in the surface layer as the canopy starts to be foliated. The physical ;presence of the leaves are felt in other quantities such as the global solar albedo and the subcanopy environment. Noticea f out as the rate of evaporation increases. The canopy resistance continues to change as LAI increases slowly during summe ?r, indicating that the canopy is not physiologically static during growing season. Canopy resistance starts to increase ab @out one month before the leaf fall, and evaporation then is controlled as if the canopy were leafless. This suggests that Aphysiological processes associated with leaves have a shorter annual period than their physical presence would suggest. ND BVI (Normalized Difference Vegetation Index) relationships with some surface measurements indicate that tower based measurements can represent at least a satellite pixel region.he top of the atmosphere and at the ocean surface have also been stGMechanical Engineering (Atmospheric Sciences) loose: Assessing American newspaper coverage of the stratospheric ozone de E300^1^Wuebbles,Donald James^1983^6^A Theoretical Analysis of the Past Variations in Global and Atmospheric Composition and F Temperature Structure^Ph.D.^University of California at Davis^162^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^592^^^^^^^^^^^^Atmospheric Sciences^Weare, Bryan C.^MacCracken, Michael C.^W-7405-ENG-48r the period 1985-1987 in the New Y HA^591^Over the last decade, advances in observation techniques coupled with an improved understanding of atmospheric chemi Ical and physical processes have demonstrated that concentrations are changing for a number of radiatively and chemically a Jctive trace gases. Many of the observed changes appear to be the result of human activities. Changing concentrations of these gases are of concern both because of their potential direct radiative effects on atmospheric temperature and climate a Lux is truly non-divergent up to intermediate depth. The second half of this thesis presents initial results of a project t Mo reconstruct the time histories of nuclear bomb-produced {+90}Sr and {+14}C in ocean surface water through measurements o Nf {+90}Sr and {+14}C in the annual growth bands of head-forming corals. One of the most important things to be learned froHm the coral time history reconstructions involves the early periods of the nuclear era when U.S. testing in the Marshall I P233^1^Lamoureux,Scott F^1994^6^Paleoclimatic Reconstruction from Varved Lake Sediments, Lake C2, Ellesmere Island, Canada^ QM.S.^University of Massachusetts^160^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^433^^^^^^^^^^^^Geology & Geography^Bradley, Raymond S.^Bradley, Raymond S.^DE-FC03-90ER61010anning of future global climate research SA^432^Varved sediments from High Arctic Lake C2 (8250'N, 7600'W), a small, deep (84 m), low-elevation meromictic lake, w Tere investigated as a paleoclimatic proxy. The combination of a short runoff and sediment transport season with the strong U density stratification of the lake lead to the formation of annual sediment couplets. The annual nature of the varves was V confirmed by {+210}Pb determinations. Additionally, previous work established that intra-lake varve correlation was high. W This study investigated varved sediments from seven distal sediment cores from depths ranging from 19 to 38 m. The cores Xexhibited similar records of near-massive marine mud overlain by 20-60 cm of finely laminated mud. Physical measurements w Yere relatively constant throughout the laminated portions of the cores studied. The cores were organic-poor, and did not p Zrovide sufficient material for radiocarbon determinations within the varved sections. A continuous record of the varved se [diments was obtained by removing slabs of sediment from the unfrozen cores. The slabs were dehydrated with repeated applic \ations of acetone followed by epoxy resin. The epoxy was cured and the slabs were thin-sectioned for the counting and meas ]uring the varves under a microscope. Well-defined marker beds were visually identified and correlated among the thin secti ^ons. Varve sequences between the marker beds were repeatedly counted and measured. Cross-dating was performed between core _ sections to identify and resolve identification errors. Cross-dating revealed that minor disturbances of the thin Lake C2 ` varves lead to varying amounts of identification error. Thin varves were most frequently missed during measurement, and w aere subsequently identified during cross-dating with other cores. Additionally, sublaminations were occasionally incorrect bly identified as separate (extra) couplets. The weighted whole-core mean errors were 1.1-11.5% for missed varves and 0.3-1 c.4% for extra varves. The net of both types of error (5.92%) estimates the error associated with varve sequences that are dnot cross-dated. Comparison between proximal and distal sediments measured by independent workers revealed no errors for a e 200 year period, suggesting that varve chronology error after cross-dating was minimal. A composite, detrended varve chro fnology was constructed from the cross-dated varve sequences in this study. Approximately 950 years of the varve composite gwere not cross-dated owing to disturbances in the sediment cores. The error due to counting errors is estimated at 57 yea hrs. A good relationship between upper air temperatures (500 m) and sediment transport into Lake C2 permits a tentative cal iibration between varve sedimentation and climate. This relationship suggests that meltwater production in the upper waters jhed is more important to sedimentation than low elevation conditions. The 3300 year composite record reveals low frequency k events similar to the d18O variations in the Agassiz, Devon, and Camp Century ice cores. Additionally, the varved record lfrom Lake C2 shows similarity with other North American proxy records during the past 500 years. The good correlation betw meen the varve record and other High Arctic proxies suggests that the tentative climatic interpretation of varve thickness nis reasonable and that the chronology is accurate. These results also suggest that the Lake C2 varve sedimentation rate has been sensitive to High Arctic and hemispheric climatic forcings.of surface-based infrared flux observations as might be p234^1^Acker,Richard H^1994^6^The Quiet (Energy) Revolution: Analyzing the Dissemination of Photovoltaic Systems in Kenya^M q.P.A.^Princeton University^107^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^435^^^^^^^^^^^^Woodrow Wilson School of Public and International Affairs^Kammen, Daniel M.^Kammen, Daniel M.^DE-FC03-90ER61010es associate sA^434^The widespread introduction and adoption of renewable energy technologies remains high on virtually every national d tevelopment policy agenda; renewable energies can assist national energy autonomy, decentralize resource management, promot ue environmental conservation, and serve as a means to reduce global warming. The track-record of efforts to turn this nobl ve ideology into successful technology transfer and dissemination, however, remains very mixed. It is a story of a few succ wesses amid many failures. Here we document and examine the diffusion of small-scale photovoltaic (PV) systems in Kenya. At x the same time that integrated energy plans and top-down models championing renewable energy futures are becoming increasi yngly common, a new power base, divorced from these grand schemes, has begun to emerge. Over the past decade, some 20,000 t zo 40,000 small PV systems, essentially all privately financed, have been installed in Kenya. Many valuable lessons for ren {ewable energy research can be found here. The Kenyan case richly illustrates the dramatic role that actors on every scale, | from grass-roots to international, can have in accelerating -- or when mismanaged, impeding -- technology transfer and th }e elevation of renewable energy systems from niche applications to a prominent role in household empowerment, and decentralized and sustainable development initiatives.ve focussed on the specific case of seasonal streamfunction anomalies assoc 235^1^Dietrich,William F^1994^6^The Concept of Critical Levels: Should Climate Change Negotiators Use It?^M.P.P.^Harvard U niversity^89^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^437^^^^^^^^^^^^Kennedy School of Government^Clark, William C.^Clark, William C.^DE-FC03-90ER61010 basic state of the model is the average of the flow for th A^436^Germany will host the first conference of the Parties to the United Nations Framework Convention on Climate Change. As host, Germany is responsible for preparing background documents for use by the Parties. The German Federal Ministry for Environment, Nature Conservation and Nuclear Safety asked researchers at the Wuppertal Institute for Climate, Environment , and Energy to serve as the analytical round of international negotiations on climate change. This policy analysis is a b ackground document for the negotiations. The paper addresses the question, "What can be learned from the use of critical l evels in other international environmental negotiations that can be used in the climate change negotiations?" The paper ex amines the use of the critical level/load concept in both the acid rain and stratospheric ozone negotiations, draws lesson s from those experiences, and applies those lessons to the climate change negotiations. It finds that critical levels will be useful in the climate change if environmental regulation have tended to bring "unifactorial" explanations to bear on q uestions like the one asked by this study. Specifically, scholars most often employ four different explanatory models to e xplain divergences in national regulatory patterns: 1) the role of domestic political institutions; 2) the institutionaliz ation, public trust, and political context of scientific information and advice; 3) the influence of international pressur e, regimes, and institutions; and 4) the role played by divergent cultural perceptions of risk. In this study I examine th e efficacy of each of these models in explaining the divergent regulatory histories of the two countries. I argue that, al one, none of these models is sufficient to account for the ten-year difference in the timing of measures to combat acid ra in. Only by highlighting the complicated interplay among these factors can one illuminate the central question that guides this study. This conclusion emphasizes the power and usefulness of multifactorial analysis.d. The schemes were applied t ison is made between the calculated pre-industrial and present atmospheres to determine whether the ozone and temperature distributions might have been substantially different before human activities influenced the global atmosphere. Results fr om this study suggest that man has altered the ozone distribution and temperature structure of the global atmosphere over this period. Increasing concentrations of CO{-2}, CH{-4}, N{-2}O and chlorocarbons, plus emissions of nitrogen oxides from aircraft, appear to be influencing the present atmosphere. The calculated pre-industrial (1850) atmosphere was found to b e measurably different from the present atmosphere. Model calculated trends in ozone and temperature for the 1960s and 197 0s are generally in agreement with the measured trends, but there are too many remaining theoretical and sampling uncertai nties for causality to be established. The generally excellent comparison of observations with the calculated distribution of trace species lends confidence to the capability of current theory to represent atmospheric processes. The results pre sented here plus calculations studying potential anthropogenic influences on the future atmosphere suggest that total ozon 238^1^Fan,Song-miao^1991^6^Atmosphere-Biosphere Exchange of CH{-4}, CO{-2}, and O{-3}^Ph.D.^Harvard University^223^Dissert ation^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^443^^^^^^^^^^^^Division of Applied Sciences^Wofsy, Steven C.^Wofsy, Steven C.^DE-FC03-90ER61010ical integration scheme for time integration is three time-level leapfrog s A^442^The atmosphere-biosphere exchange was measured of CO{-2} and O{-3} in a tropical rain forest near Manaus, Brazil dur ing April and May 1987, and of CO{-2}, CH{-4}, and O{-3} in an arctic tundra of southwestern Alaska during July and August 1988. Vertical fluxes were measured directly using the eddy correlation technique in the surface layer; concentrations of the trace gases were also measured sequentially at eight altitudes from near the ground to about 10 meters above canopy. Forest floor respiration was measured using soil enclosures in the tropical forest. Nocturnal respiration averaged 6.20.7 (s.e.) gC/m{+2}/d by the forest ecosystem (~85% from the forest floor) but 0.730.07 gC/m{+2}/d by the tundra ecosystem. Net ecosystem exchange (NEE) of CO{-2} increased almost linearly with intensity of light by 0.036 (gC/m{+2}/d)/(W/m{+2}) i n the forest, suggesting that canopy photosynthesis of a well-watered forest is primarily controlled by photosynthetically active radiation. Solar irradiance also provided the primary control on the NEE of CO{-2} in the disparate tundra ecosyst em, although the relationship was curvilinear and photosynthesis was quickly light saturated (Pmax ~ 2.5 gC/m{+2}/d, I{-1/ 2} ~ 60 W/m{+2}). Changes in the distribution of cloud cover, associated for example with climatic change, might induce gl obally significant changes in primary productivity and carbon storage. Methane emission averaged 251 mgCH{-4}/m{+2}/d fro m the site of tundra ecosystem. Methane fluxes were apportioned to various habitats, using a SPOT satellite image of the s ite to classify surface vegetation at 20x20m resolution. Dry tundra (water level 5 cm below soil surface) was found to emi t 113 mgCH{-4}/m{+2}/d and wet tundra (water near the surface) 293 mgCH{-4}/m{+2}/d. Fluxes from lakes depended on wind speed, averaging 576 mgCH{-4}/m{+2}/d, where wind speed was 5 ms{+-1}. Results were used to assess errors accrued in scal ing up the chamber data to larger scales. Methane emission from global tundra may be estimated with an error of 50% becaus e the satellite could not fully resolve heterogeneous methane producing habitats. Mean ozone deposition flux was ~1.0x10{+ 11} molecules cm{+-2}s{+-1} in the tropical rain forest and in the arctic tundra, although daytime concentrations of O{-3} in the surface layer averaged 5 ppb over the forest and 25 ppb over the tundra. The mean ozone deposition velocity at ~10 m above canopy of the forest was 0.26 cm s{+-1} in the night and 1.8 cm s{+-1} in the day, regulated by turbulent transpo rt and stomatal activity. The ozone deposition velocity measured at 12 m above the tundra was found inversely proportional to wind speed, averaging 0.13 cm s{+-1} in the night and 0.25 cm s{+-1} in the day.mechanical problems were highlighted 239^1^Salathe,Eric^1994^6^The Interaction of Upper-Troposphere Water Vapor and the Earth's Infra-Red Radiation Field^Ph.D. ^Yale University^128^Dissertation^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^445^^^^^^^^^^^^Geology and Geophysics^Smith, Ronald B.^Smith, Ronald B.^DE-FC03-90ER61010on mangrove forest structure and evaluates the role o A^444^A fundamental problem in predicting the response of the climate to anthropogenic perturbations to the atmospheric ra diation field is understanding the role of water vapor. Water can provide a positive feedback to a temperature perturbatio n that is easily understood since a warmer atmosphere can contain more water and be more opaque. This feedback almost cert ainly occurs in the lower troposphere where shallow convection quickly transports water vapor into the boundary layer from the sea surface and maintains constant high relative humidity. The upper troposphere, however, is isolated from the under lying sea surface over large regions of the globe that are characterized by persistent sinking motion. Given the lack of a comprehensive long-term record of global upper-tropospheric water vapor, its role in climate processes is an unresolved q uestion and is the underlying motivation for the work in this dissertation. The first two chapters present introductory ma terial. In Chapter Three, the ability to measure moisture and to model the radiation field in the upper-troposphere is exa mined. Radiances observed by the GOES-VAS 6.7 um channel are compared to computations from simultaneous aircraft soundings of temperature and moisture. This comparison shows that all three models overestimate the observed brightness temperature s but reproduce the full range in observed brightness temperatures. Possible sources for this bias are investigated, and i t is concluded that no one mechanism can alone account for the observed discrepancies. In Chapter Four, regional and seaso nal characteristics of upper tropospheric moisture and the ability of a circulation model to capture them is examined. Lar ge-scale variability of moisture in the upper troposphere in 1989 is examined using ECMWF model analyses and TOVS satellit e radiances. Radiances computed from the ECMWF analyses reproduce the general locations and seasonal cycle of the TOVS-obs erved moisture features, but lack the moisture gradients and seasonal contrasts than indicated by the TOVS observations. D ynamically, the TOVS-observed regions of significant subtropical dryness are correlated with persistent subsidence indicat ed by ECMWF 300mb vertical velocity analyses. In Chapter Five, the impact of infra-red radiative heating on the evolution of observed atmospheric profiles and the vertical distribution of water vapor is considered. Gravity wave motions are expl ored as a mechanism to produce vertical layering of moisture and infra-red cooling is shown to slightly amplify the gravity wave. The static and dynamic stability of moist layers is explored.elevant to the functioning of the Earth system, but 240^1^Blasch,Kyle W^1994^6^Analysis of the Earth's Schumann resonance^M.S.^Massachusetts Institute of Technology^192^Thesi s^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^447^^^^^^^^^^^^Earth, Atmospheric, and Planetary Sciences^Williams, Earle^Williams, Earle^DE-FC03-90ER61010O2 between the atmosphere and terrestrial ecosystems of 64N to 90N A^446^Descriptions of two formulations describing the Earth's Schumann resonance were investigated to provide a quantitati ve analysis of the resonance. The convective instability approach predicted higher values for the resonance than the absol ute instability approaches. Ratios methods for determining the frequency dependent source term, M(w), and attenuation were developed for the single source case. The geometric structure of the resonance was used to isolate time periods and locat ions when the ratios closely approximated the single source case. Quantitative comparisons were made with observed Schuman n Resonance data from Table Mountain, California and N.W. Cape, Australia. Agreement was within an order of magnitude for features in the first three modes, although ratios near the singularities tended to overestimate the observed values.ty", e measurements may not provide a very sensitive indication of the impact of human activities on the global atmosphere. Monitoring of changes in the distributions of ozone and temperature should be more useful.^^449^^^^^^^^^^^^Earth and Planeta 301^1^Toggweiler,John Robert^1983^6^A Multi-Tracer Study of the Abyssal Water Column of the Deep Bering Sea, Including Sed iment Interactions; A Six Zone Regionalized Model for Bomb Radiotracers and CO{-2} in the Upper Kilometer of the Pacific O cean^Ph.D.^Columbia University^421^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^594^^^^^^^^^^^^Geochemistry^Broecker, Wallace S.^Broecker, Wallace S.^DE-AC05-84OR21400E (analyzed using weekly data) is found to rise quickly in late May A^593^This thesis is made up of two parts which are linked together by a common concern with the Pacific Ocean. Each part consists of five chapters which can be briefly summarized as follows. The abyssal waters of the Bering Sea lie in a high l atitude marginal basin and are partially isolated behind the islands of the Aleutian Arc. Surface waters are characterized by very low salinities and high biological productivity. Sediments covering the abyssal plain are accumulating at a rate of about 30 cm/1000 yrs and have opal contents in excess of 30%. In temperature and salinity properties deep Bering Sea wa ter appears very similar to water in the adjacent Pacific. In chemical properties, however, Bering Sea water is distinctly labeled by very high dissolved silica concentrations and reduced oxygen content. The basin's simple geometry permits a st raightforward parameterization of lateral exchange with the Pacific coupled with a standard one dimensional model, Munk (1 966). Pacific water of sill-depth composition flows into the bottom layer. The distribution of bottom area is apportioned into various levels of the model to simulate sediment interactions. The model is designed to test for degree of lateral vs 242^1^Goldstein,Allen Hyman^1994^6^Non-Methane Hydrocarbons Above a Midlatitude Forest: Biogenic Emissions and Seasonal Co ncentration Variations^Ph.D.^Harvard University^133^Dissertation^^^Graduate Fellowships for Global Change; National Institute for Global Environmental Change (NIGEC)^^^^^^^451^^^^^^^^^^^^Chemistry^Wofsy, Steven C.^Wohlpart, A., and Steven C. Wo A^450^This dissertation presents observations of 1) non-methane hydrocarbon emissions from a northern midlatitude forest, and 2) C2-C6 hydrocarbon concentrations over an annual cycle. The observations are analyzed to determine the dependence of biogenic olefin fluxes on temperature, light, and season and to obtain a measure of the annual mean and seasonal variatio n of OH concentration in the Northern Hemisphere. An automated system measuring hydrocarbon concentrations and vertical gr adients was constructed. Measurements were obtained continuously from July 1992 to November 1993 at Harvard Forest, Peters ham, Massachusetts. The longest gap in the data was eight days. Mean emission rates for isoprene, ethene, propene and 1-bu tene were 11.8, 2.63, 0.97, and 0.37 x 10{+10} molec/cm{+2}/s respectively, in summer 1993, derived using a micrometeorolo gical gradient technique. Isoprene emission began several weeks after canopy photosynthesis, and decreased rapidly at leaf senescence. Emissions of ethene, propene and 1-butene had a longer seasonal cycle than isoprene. Fluxes of ethene increas ed relative to the other olefins during leaf senescence. Emissions of ethene, propene and 1-butene were correlated with in cident sunlight, while isoprene rose in the morning with temperature and declined in the afternoon with light. These emiss ion patterns indicate above-ground biomass sources for all species. The observations challenge the assumption that propene and 1-butene global inventories are dominated by oceans, biomass burning and fossil fuel combustion, suggesting instead t hey are dominated by the terrestrial biosphere. Seasonal variations of background concentrations for C2-C6 alkanes, and ac etylene, were defined by the 0.1 quantile in 30 day periods. Maxima occurred in winter and minima in summer. Species that react fastest with OH reached their winter peak earliest, and declined earliest in the spring. The ratios of winter to sum mer concentration were observed to be uniform for the shortest lived hydrocarbons. We argue that the uniform ratios reflec t seasonal steady-state conditions, and provide a direct measure of the mean ratio of OH concentrations in summer to winte r at northern midlatitudes, 10 2. Simulations of ethane data using a three-dimensional chemical tracer model and a box model constrain OH at northern midlatitudes to a mass weighted annual mean of 7 x 10{+5} molec/cm{+3} 50%. Climate, and 243^1^Youngblood,Debra A^1994^6^Further Development and Testing of a Bimodal Aerosol Dynamics Model^M.S.^Colorado State Un iversity^151^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^453^^^^^^^^^^^^Atmospheric Sciences^Kreidenweis, Sonia^Kreidenweis, Sonia^DE-FC03-90ER61010y","Reynolds, James F.","DEAI0181ER60012","Carbon, Climate, and A^452^A previously reported bimodal monodisperse aerosol model is further developed and tested. The starting point is the BImodal MOnoDisperse Aerosol Model (BIMODAM I) which was developed to model the formation of ammonium sulfate ((NH{-4}){-2 }SO{-4}) particles from sulfuric acid (H{-2}SO{-4}) vapor. The model follows the evolution of two monodisperse modes where  each mode, i, is characterized by a unique mean diameter and the number of particles with that mean diameter. The aerosol  distribution is assumed to undergo typical atmospheric processes such as condensational growth, coagulation, nucleation, and deposition. In BIMODAM I, the effect of each process on the aerosol distribution is represented as a rate equation. Th e prognostic equations are coupled, so a variable time step differential equation solver is utilized to simultaneously sol ve the system of equations to predict the mass and number concentration in each mode. The diameter of each mode is diagnos ed from the mass and number concentrations. In the first part of this work, two new parameterizations were developed for B IMODAM I. First, a condensation rate factor was developed to account for the lack of polydispersity in the model. Second, a criterion was developed which dictates when the two modes may be merged without generating large errors. In the second p art of this work, a new version of the model (BIMODAM II) was developed to give the same accurate results as BIMODAM I wit hout using the variable time step differential equation solver. A key development in BIMODAM II is a parameterization for the process of homogeneous nucleation. This parameterization is based on the approximation of the time-dependent nucleatio n rate with a triangular function; using this approach, only two parameters are needed to predict the total number of part icles resulting from a nucleation event. The two parameters are correlated to chemical source rate and relative humidity. Therefore, prediction of the number concentration of particles resulting from a nucleation burst depends on knowing the re lative humidity and determining the chemical source rate. This development has been shown to perform well in the presence and absence of preexisting particles and over short and long time scale simulations. Further developments in BIMODAM II in clude simple analytical solutions of the differential equations for coagulation and deposition. Using a mass balance equat ion, a simple solution was also derived to predict the amount of sulfuric acid in the vapor phase at any time during the s imulation. From this calculation, the amount of mass in the aerosol phase is calculated by subtracting the amount in the v apor phase from the total amount of sulfuric acid produced during any given time step. By using the simplifications and pa rameterizations mentioned above, computational time is saved by eliminating the variable time stepping differential equati on solver. This model is shown to perform well when compared against a simulation which uses a more detailed description of the aerosol size distribution. Vegetation" "Prior, S.A.","1986","Field Studies of the Water Relations and Growth Respo 244^1^Grovenstein,John David^1993^6^The Role of Cloud Condensation Nuclei in Understanding Climate Change^M.S.^North Carol ina State University^46^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^455^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Saxena, Vinod K.^Saxena, Vinod K.^DE-FC03-90ER61010obal Energy and Carbon Dioxide Emissions !A^454^It has been suggested that reducing fossil fuel emissions could cause global warming. Observed increases in sulfate "derived cloud droplet number concentration indicate a cooling of 2-3 Wm{+-2} in eastern North America. Reduction of SO{-2} # derived from fossil fuels as mandated by the amended Clean Air Act would cancel this cooling. When SO{-2} is released it $will form Cloud Condensation Nuclei (CCN). CCN have been implicated in climate regulation through their role in cloud-medi %ated albedo. SO{-2} derived cooling is obtained by a simple diagnostic model based on the relationship between SO{-2} emis &sions and cloud reflectivity. Increased SO{-2} emissions will decrease cloud droplet size. Could droplet size influences c 'loud albedo. Increased SO{-2} emissions will increase cloud albedo by decreasing cloud droplet size. Reducing SO{-2} emiss (ions will have the opposite effect. We use three scenarios to assess the impact of fossil fuel emissions. These scenarios, ) after scenarios suggested by the Intergovernmental Panel on Climate Change (IPCC), are growth of emissions by 2% per year *, a reduction by 2% per year, and a "business as usual" scenario of 0% per year. Model results of these three scenarios ar +e presented. A 2% per year reduction of fossil fuel emission indicates a 30% reduction in SO{-2} derived cooling in the ne ,xt 50 years. Two percent growth per year for 50 years will cause a 40% increase in SO{-2} derived cooling. We will also dilscuss the sensitivity of regional climate to changes in fossil fuel emissions. There exist three possible mechanisms for t .245^1^Seielstad,Carl A^1994^6^Holocene Environmental History at Chatterton Springs on the Southern Coastal Plain of Georgi /a^M.A.^University of Georgia^153^Thesis^^^National Institute for Global Environmental Change (NIGEC)^^^^^^^457^^^^^^^^^^^^Geography^Brook, George A.^Brook, George A.^DE-FC03-90ER61010is","University of Colorado","158","none","","Barry, Roger G 1A^456^The Chatterton palaeoecological record provides the first evidence linking climate, fire, man, and the development o 2f Coastal Plain ecosystems. Analysis of pollen, charcoal, and inorganic sediments from a peat deposit in Coffee County, Ge 3orgia reveals that the early Holocene (10,000-4,000 BP) experienced wetter conditions than present, while the late Holocen 4e was slightly drier than present. Wetter periods were characterized by oak dominance and drier periods by pine dominance. 5 Pine forest, eolian sand movement, fire, and human activity have been closely linked for the last 9,500 years. Palaeoecol 6ogical evidence from the site supports the argument that the Middle Archaic period may have witnessed a general depopulati 7on of the Chatterton area by indigenous peoples. _Zea mays_ (corn) pollen was identified at 2,000 BP, 1,300 BP, and 1,000 8BP, providing the first direct evidence of the presence of maize in the Woodland period on the inner Coastal Plain of Georgia."Ph.D.","Dissertation","University of California","162","none","","Weare, Bryan C.","Atmospheric Sciences","MacCracke :246^1^Freer,Michael E^1994^6^Temporal and Spatial Variations of Methane Emissions from the Sabine River Floodplain of Sout ;heast Texas; The Role of Dissolved Organic Carbon (DOC) and Other Physicochemical Parameters^M.S.^Lamar University^65^Thes A^458^The Sabine River floodplain is a flat broad watershed containing a diverse assemblage of blackwater wetland habitats ?. Concentrations of dissolved organic carbon (DOC) in the floodplain as well as the estuary are typically very high (15-20 @ mg/l). In this study we compared methane fluxes across a gradient of three different habitats, within the floodplain, tha At extended from the outer reaches of the basin to the river proper (i.e., blackgum _Nyssa aquatica_, cypress _Taxodium dis Btichum_, and arrowhead _Sagittaria_ spp.), as well as a fourth station (a _Spartina_ marsh) within the Sabine-Neches estua Cry. Methane emissions were highly variable and range from -0.0007 to 1640 mg m{+-2} d{+-1}, with the highest rates in July D 1993. Fluxes were significantly correlated (both positively and negatively) with precipitation (p<0.01); natural periods Eof flooding and drought were primarily responsible for the wide range of emissions. Methane consumption rates had little e Fffect on total emissions due to ebullition and plant mediated transport mechanisms. Laboratory incubation experiments indi Gcated that UV-B treated humic substances were preferentially utilized by methanogens over untreated humics. Thus, variability of light penetrance across the floodplain may affect the quality of DOC.eruse efficiency,drought,CO2 enhancement,eco I247^1^Reilly,John Matthew^1983^6^An Economic Analysis of Global Energy and Carbon Dioxide Emissions^Ph.D.^University of Pe Jnnsylvania^173^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^461^^^^^^^^^^^^Economics^Adams, F. Gerard^Edmonds, James A.^DE-AC05-76OR00033n on biogeographical distribution of C4 plants","Ph.D.","Dissertation","Duke University","156","Th LA^460^A energy-economic model of possible future carbon dioxide emissions is presented and simulated to the year 2050. The M model endogenously determines the set of energy prices that balance supply and demand for energy. Based on these simulati Nons, energy use and carbon dioxide emissions are shown to increase substantially through the year 2050, with an increasing O share of emissions and energy use from outside the OECD countries. The model is simulated to consider the level of global P emission taxes required to meet carbon dioxide concentration targets of 400, 600, and 800 parts per million (ppm) concent Qrations of atmospheric carbon dioxide and to control emissions to rates that would limit the temperature increase to .2, . R5 and .7 C. per decade. The fossil fuel taxes in constant 1975 dollars required by 2050 to meet concentration targets rang Sed from $107 (800 ppm constraint) to $372 (400 ppm constraint) per ton of carbon and from $0 (.7 C.) to $120 (.2 C.) to li Tmit the rate of increase in temperature. The required level of taxes increase over time. The United States acting alone to control emissions is shown to have very little effect on slowing the rate of climate change. survive through the summer VA^462^Two topics are included in this thesis: (1) The application of linear free energy relationship (LFER) to marine chem Wistry is discussed and (2) winter carbonate data collected in the northern North Atlantic Ocean, mainly the Norwegian and XGreenland seas, are analyzed. First, the occurrence of LFER has been confirmed by the stability constant data reported in Ythe cited literature. Comparison of LFERs was made between the condition of zero ionic strength and that of 0.7 ionic stre Zngth which is considered similar to the condition in the marine environment. The application of LFERs yielded estimates of [ some undetermined stability constants, especially for carbonate and bicarbonate complexes and ion pairs, and adjustments \to some data reported in the literature needed to be made. The goals achieved in the present work were: (1) to provide the ] evidence of LFERs in seawater in terms of the logarithms of stability constants (thermodynamic and stoichiometric at 0.7 ^ionic strength) at 25C and 1 atmosphere; (2) to analyze the reason that the separate LFERs form and indicate their appear _ances occur only when log K{-MF} and log{-MF} at 0.7 ionic strength are correlated with other logarithms of stability cons `tants; (3) to suggest that separate LFERs are dependent on the type classification of metal ions according to Lewis' theor ay; (4) to provide the improved stability constants and compare them with the reported values from literature and to predic bt unknown stability constants, mainly for carbonate and bicarbonate complexes and ion pairs. Secondly, excess CO{-2} penet cration in the northern North Atlantic Ocean in winter has been revealed based on carbonate data. The direct carbonate data d in wintertime were collected on the HUDSON 82 cruise to the Norwegian and Greenland seas. The results indicate that the w ehole water column in the two seas has been contaminated by anthropogenic CO{-2}, more so in the Greenland sea than in the fNorwegian sea and more in the western basin than in the eastern basin. Observations of the apparent oxygen utilization and tritium data support this conclusion. _Pueraria lobata_ Ohwi (Kudzu) and _Lonicera japonica_ Thunb. (Japanese honeysuckl h249^1^Olson,Eric J^1981^6^Calcium in the Equatorial Pacific Ocean^M.S.^Oregon State University^84^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^465^^^^^^^^^^^^Oceanography^Chen, Chen-Tung A.^Chen, Chen-Tung A.^DE-DOE8/EV-10611he effects of th jA^464^The calcium concentration of seawater was measured for samples obtained from the recent Hawaii-Tahiti Shuttle Experi kment. The complexometric titration used for the determination of calcium was shown to be free of interference from other a llkaline earth elements at the 0.1% level of accuracy obtained. However ratios of interferant to calcium larger than those mfound in seawater did cause significant loss of accuracy. The results of the investigation of the vertical distribution of n calcium, in the equatorial region sampled, suggest that physical-circulation processes are more important that local-vert oical production and dissolution of CaCO{-3} in creating the relative extreme observed. These samples from depths of 1000 m p and less, have specific calcium values that inversely correlate with salinity and temperature. The lowest values of norma qlized (to 35/{-} salinity) calcium are found in the warm surface waters of highest salinity and appear to reflect biolo rgical depletion in the relatively unmixed waters of the central gyre. The higher specific calcium values are found in less s saline waters from higher latitudes and reflect the higher "preformed" calcium values found in colder waters near the pol tar fronts. This "preformed" dependence can been seen in cross-sectional comparison of calcium concentrations (normalized) uacross the equator. Here the calcium distribution has boundaries consistent with those between particular circulation features such as equatorial currents and possibly upwelled intermediate waters.tion patterns while still incorporating CO{2{ w250^1^Wei,Ching-Ling^1985^6^Carbonate Chemistry of the North Pacific Ocean^M.S.^Oregon State University^148^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^467^^^^^^^^^^^^Oceanography^Chen, Chen-Tung A.^Chen, Chen-Tung A.^81-EV-10611^19x-89608C yA^466^This thesis covers a wide area of the North Pacific Ocean, latitudinally from 10 to 55N and longitudinally from Ja zpan to the U.S. coast. With two longitudinal cruises as the main data sources and selected literature data sets as supplem {entary data source, the distribution of physical and chemical properties in the North Pacific Ocean is presented. AOU, pH, | total CO{-2}, and nutrients (nitrate and phosphate) are interrelated parameters. Along our two longitudinal sections they } all show a core structure underlying the salinity minimum layer. From these oxidation related parameters we obtain a conc ~lusion that the subsurface water of the eastern North Pacific Ocean is older than that of the western North Pacific Ocean.  Alkalinity, calcium, and silicate show a monotonically increasing trend with depth to the deepest sampling depth. The alk alinity data can be used as a water mass tracer. Different water masses which show their own mixing trends can be identifi ed when the correlation of normalized alkalinity with temperature is scrutinized. The vertical distribution of the normali zed alkalinity shows a maximum core at a depth of about 2500 m in the North Pacific Ocean. Not only the calcium carbonate dissolution but also the circulation in the deep and bottom layer plays a role in this normalized alkalinity maximum core. Our analysis of carbonate data shows that about 25% of the increase in total inorganic CO{-2} of deep water, after leavin g from the Southern Ocean to the North Pacific, is contributed by inorganic CaCO{-3} dissolution. There is no significant difference of inorganic carbon/organic carbon ratio between our two sections. However, it was found that the eastern secti on has a higher total TCO{-2} input than that of the western section. The degree of saturation with respect to calcite and aragonite was calculated from all the available data sets. Mr. Ahmed Rushdi and Professor R.M. Pytkowicz are working on t he effect of Mg on the formation and the properties of magnesian calcites. There are metastable forms of these compounds w hich may have been interpreted as stable ones in solubility determinations. Some revisions of degree of saturation may be called for in the future. Four selected cross-sections, three longitudinal and one latitudinal, show that a large volume o f the North Pacific is undersaturated with respect to CaCO{-3}. The saturation horizon generally shows a shoaling from the west to the east and from the south to the north in the North Pacific Ocean. It was found that lysocline falls on a depth much deeper (about 2500 m deeper) than the saturation horizon of calcite and several hundred meters shallower than the CC D (calcium carbonate compensation depth) depth. Our results support the kinetic point of view on the CaCO{-3} dissolution mechanisms. The direct approach on the fossil fuel increase signal in seawater is adopted in this thesis. A new set of pre formed equations of alkalinity and total CO{-2} was obtained from a more updated GEOSECS data. Our results show that the p enetration depth of fossil fuel CO{-2} is strongly related to the surface oceanographic circulation. The shallowest penetr ation depth is less than 300 m found in the eastern equatorial region where the upwelling prevails and the deeper penetration depth is deeper than 2000 m off Japan where an interaction of Oyashio and Kuroshio currents in found.ssed _Abutilon t study, for four lakes in Wisconsin, U.S.A, does not produce valuable results. The second study, for 27 lakes throughout C age CO{-2} gas exchange rate of 18.2 moles/m{+3}/yr by fitting radiocarbon time histories. In modeling the steady distribu tion of CO{-2} with a regional model of this type we show that it is possible to predict the net biological removal of car bon from the mixed layer by fitting {+13}C/{+12}C ratios in surface water. The six-zone model represents the first attempt to couple the biological uptake of carbon with an upper ocean model in order to simulate the meridional variation in pCO{-2}.Seasonal variations of background concentrations for C2-C6 alkanes, and acetylene, were defined by the 0.1 quantile i 302^1^Herczeg,Andrew Leslie^1985^6^Carbon Dioxide Equilibria and {+13}C Studies in Some Soft Water Lakes^Ph.D.^Columbia U niversity^263^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^596^^^^^^^^^^^^Geochemistry^Broecker, Wallace S.^Broecker, Wallace S.^DE-AC05-84OR21400rbons. We argue that the uniform ratios reflect seasonal steady-state conditions, and pro A^595^A method for determining the hydrogen ion concentration of fresh waters is presented that involves total dissolved i norganic carbon measurements (DIC or CO{-2}) and CO{-2} partial pressures (P{-CO2}) measurements rather than pH electrode measurements. Values of pH calculated from DIC and P{-CO2} measurements in some softwater lakes at the Experimental Lakes 253^1^Bermudez,Alejandra Paez^1982^6^Carbon Dioxide Enrichment: Its Direct Effects and Its Interaction with Water Stress R elative to Apical Dominance and Growth of Pea and Tomato Plants^Ph.D.^Duke University^171^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^473^^^^^^^^^^^^Botany^Hellmers, Henry^Strain, Boyd R.^DE-AI01-81ER60012 plant than did the humid air A^472^A continued increase in atmospheric carbon dioxide could have a profound effect upon plant growth, resulting in a ch ange in composition and structure of agricultural and native ecosystems. The objectives of this study using increased atmo spheric CO{-2} were: 1) to determine its effects on apical dominance; 2) to obtain information on changes in growth respon se for species and cultivars; 3) to investigate the interacting effect with water stress on plant growth and development. Alaska and Snow pea (_Pisum sativum_) and New Yorker and Better Boy tomato (_Lycopersicum esculentum_) plants, were grown from seeds under controlled environments in the Duke University Phytotron. The results produced by CO{-2} enrichment were: 1) Apical dominance was not altered, 2) Seedling emergence was unaffected. However, the growth response in terms of plant height, leaf thickness, dry matter production and flowering varied with the species and the cultivars within species and was inconsistent for determinate and indeterminate cultivars. While even determinate and indeterminate plants were not con sistent in their response, growth form of indeterminate plants was more affected. 3) The water status was usually not affe cted by the CO{-2} level when the plants were well-watered. When water was withheld both total leaf water and osmotic pote ntial decreased, with a slower decrease under high CO{-2}. Plants maintained a positive turgor potential under high CO{-2} and did not wilt when water-stressed. The differences in water potentials apparently were due to reduced stomatal conduct ance and transpiration rate. Additional CO{-2} caused no effect on branch number in stressed or non-stressed plants. Water stress completely inhibited branch development in pea and significantly reduced it in tomato. Elevated CO{-2} partially c ompensated for this inhibiting effect and resulted in more rapid recovery of water-stressed plants. These results are of e cological significance. They indicated that as atmospheric CO{-2} increases, there will be improved water use efficiency, and also, changes in canopy shape may occur in crop stands and native ecosystems. This would be due to response differences of species, varieties and cultivars. species have similar patterns of carbon exchange rates, and how carbon exchange dy 254^1^Sasek,Thomas William^1983^6^Growth and Biomass Allocation Patterns of _Lonicera japonica_ Thunb. and _Lonicera sempe rvirens_ L. under Carbon Dioxide Enrichment^M.S.^Duke University^80^Thesis^^^Carbon, Climate, and Vegetation^^^^^^^475^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AI01-81ER60012h species showed similar wholeseedling carbon uptake, in A^474^Japanese honeysuckle (_Lonicera japonica_) and coral honeysuckle (_Lonicera sempervirens_) were compared in their re sponses to atmospheric carbon dioxide enrichment. The exotic Japanese species responded much more to CO{-2} than did the n ative coral honeysuckle. The relative increase in growth of the exotic was related to more efficient biomass utilization, earlier branching along the stem, and more carbon allocation to new leaf production. The compounding effects of branching, whether it occurs sooner or goes on longer into the growing season, are most important in producing differential growth o f the two species and to increasing the competitive ability of the exotic over the native vine and of the vines over non-v ine species. These intrinsic differences between the two _Lonicera_ species would probably be even further magnified if ot her environmental stresses were present. This study suggests that Japanese honeysuckle will become more aggressive as an invading exotic as the atmospheric CO{-2} continues to increase.e tolerance,competition,carbon balance,growth,photosynthes 255^1^Riechers,George Herman^1983^6^The Effects of Carbon Dioxide Enrichment on Two C-4 Grassland Species^Ph.D.^Duke Unive rsity^92^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^477^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AS05-83ER60177esis","Duke University","52","In order to study C{3} and C{4} plant growth in atmospheric CO{2} levels rang A^476^The gradual, continuing CO{-2} enrichment of the global atmosphere is certain to have numerous effects on plants. It is well documented that these effects will not be uniform among species, but rather some species will be greatly affected , others relatively little. Because of this species specificity in the response to CO{-2} enrichment, effects on the compe titive balances among species are anticipated. Photosynthetic pathway is one of the major factors upon which the response to CO{-2} depends. Plants with the C-3 pathway are predicted to have larger growth responses than C-4 species. However, mo st of the studies upon which this prediction is based were either short-term experiments, or were performed at low irradia nces which may have severely limited the photosynthesis of the C-4's. Therefore, in this study two C-4 species -- _Andropo gon scoparius_ and _Bouteloua gracilis_ -- from the Great Plains grasslands were grown for an extended period, under irrad iances of approximately 1000 sec{+-1}m{+-2} PPFD, and at three CO{-2} concentrations -- 350, 675 and 1000 ll{+-1}. A significant effect of enrichment to 675 ll{+-1} on the growth of both species was demonstrated. After 9 weeks, _Andropog on_ had nearly 50% more leaf area at 675 ll{+-1} than at 350 ll{+-1}. _Bouteloua_, after 7 weeks, had an 80% increase in leaf area. Well-watered plants grown at 1000 ll{+-1} were generally no longer than those at 350 ll{+-1}. A period o f drought stress was also imposed. The interaction between this stress and CO{-2} enrichment was such that elevated CO{-2} tended to reduce the severity of the stress, and that other under the stress treatment the CO{-2} effects may have been e nhanced. Photosynthetic capacity of the plants grown at elevated CO{-2} was not reduced. Similarly, there was no evidence of excessive starch accumulation in the leaves grown at high CO{-2}. For example, specific leaf weights were reduced in plants grown at 675 and 1000 ll{+-1}, not increased as would be the case with starch accumulation.standing of the control 256^1^Tolley,Leslie Carroll^1982^6^The Effects of Atmospheric Carbon Dioxide Enrichment, Irradiance and Water Stress on Se edling Growth and Physiology of _Liquidambar styraciflua_ and _Pinus taeda_^Ph.D.^Duke University^258^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^479^^^^^^^^^^^^Botany^Strain, Boyd R.^Strain, Boyd R.^DE-AI01-81ER60012mount of glucose A^478^In order to predict possible effects of increasing atmospheric carbon dioxide on woody plant succession and communit y species composition, more detailed information is needed on the individual response of successional species to this chan ging environmental factor. The objective of this study was to investigate the growth and physiological response of two imp ortant successional woody species, _Liquidambar styraciflua_ L. (sweetgum) and _Pinus taeda_ L. (loblolly pine) to long te rm CO{-2} enrichment. Carbon dioxide effects were studied under different irradiance and soil moisture conditions since th ese environmental factors, as well as nutrient availability, influence their pattern of invasion into abandoned fields and establishment under forest canopies in the North Carolina piedmont. Growth and physiological experiments were conducted i n controlled environment facilities at the Duke University Phytotron. Elevated atmospheric CO{-2} concentration enhanced g rowth with the greatest increase in height, leaf area, basal stem diameter and total dry weight seen for sweetgum seedling s grown under high irradiance. Increases in dry matter accumulation were associated with early CO{-2} enhancement of net a ssimilation rate, with increases in amount of leaf surface area contributing more towards maintenance of larger size as se edlings aged. For sweetgum seedlings in particular reduction of growth by low irradiance and soil drought under normal atm ospheric CO{-2} was compensated for by growing plants under elevated CO{-2}. Photosynthetic acclimation of sweetgum and lo blolly seedlings was not significantly altered by increasing atmospheric CO{-2}. However, CO{-2} enrichment had a substant ial differential effect on drought tolerance of these two species. Sweetgum seedlings grown at elevated CO{-2} maintained higher plant water potentials and net photosynthetic rates during a period of drought than when grown at present day CO{-2 } level. In addition water use efficiency in these seedlings was also increased. In contrast CO{-2} enrichment had much sm aller effects on total plant water potential, net photosynthesis, transpiration and water use efficiency of loblolly seedl ings. Physiological and growth response data in this study strongly suggest that the continued increase in atmospheric CO{-2} may influence distribution patterns of these two species primarily in open fields.ies have considered whether the pre tterns might be indicators of future climate as the earth warms from increasing greenhouse effect. The correlation coeffic ients between precipitation and temperature have been computed for individual stations, for state averages and for regiona l averages for each month and each season of the year. The linear regression analysis has also been conducted on each regi on for each of the four seasons. Areas of both negative and positive precipitation-temperature correlations were found in the United States. Over most areas, summer precipitation and temperature are negatively correlated, which indicates that w arm summers tend to be dryer and colder summers tend to be wetter. The only notable area where a significant positive corr elation was found is south of the Great Lakes bounded in the east by the Appalachian mountains. The contribution to the to tal correlation from variations of various time-scales was also analyzed in terms of moving-average filtering technique. T he correlation between precipitation and temperature were analyzed for three frequency bands - short (shorter than 5 years ), medium (between 5 and 15 fifteen years), and long (longer than 15 years) cycles. Although both negative and positive pr ecipitation-temperature correlations were found for all cycle bands, over most areas of the United States, significant correlation mainly occurs from variations of short and medium cycles.. In fact, phosphoruslimited seedlings showed the grea 258^1^Lu,Yu^1990^6^Modeling Tropospheric OH Chemistry^M.S.^Oregon Graduate Institute, Global Change Research Center^244^Th esis^^^Carbon, Climate, and Vegetation^^^^^^^483^^^^^^^^^^^^Environmental Science and Engineering^Khalil, M. Aslam K.^Rasmussen, R.A., and M.A.K. Khalil^DE-FG06-85ER60313^reduced photosynthetic capacity and tissue phosphorus concentrations in A^482^The hydroxyl radical, OH, is perhaps the most important reactive species in the troposphere, which reacts a wide ran ge of trace gases and free radicals. The OH chemistry is coupled to almost all trace gas cycles. Environmentally important trace gases such as CO, CH{-4}, and many nonmethane hydrocarbons are removed principally by reacting with OH. The distrib ution of the concentrations of the highly reactive OH radicals have been obtained with a detailed photochemical model. The  model contains the information on the physical nature of the atmosphere such as temperature, pressure, and solar intensit y as well as on the distributions of some key species, and chemical kinetic and photochemical data, and includes the cycle s of HO{-x}, NO{-x}, and other reactive compounds. Although the concentrations of a sequence of trace gases and free radic als were calculated with the model in this study, this thesis mainly covers the tropospheric distributions of the hydroxyl  radical and its major buffer, the hydroperoxyl radical (HO{-2}). The model results, which are generally consistent with v arious measurements and model predictions, show that OH has a strong diurnal variations as well as clear vertical, seasona l, and latitudinal variations due to its high reactivity and short lifetime. As a special aspect of this thesis, the night time OH, which has not been of concern in previous model calculations, are presented and discussed in detail. The model re sults show that the nighttime OH has also clear vertical, seasonal, and latitudinal variations, with its seasonally and gl obally averaged concentration of 9.6x10{++3} molecules/cm{+3}, which is two orders of magnitude less than the seasonally a nd globally averaged daytime OH concentration, 1.2x10{++6} molecules/cm{+3}. In addition, the nighttime OH assumes a more significant role in winter in the midlatitudes in the middle troposphere. The mechanism of production and destruction of h ydroxyl radicals in the troposphere has been explored with two methods. First, by comparing the reactions directly affecti ng OH, it is concluded that the mechanism for production of OH is significantly different between daytime and nighttime, w hile the mechanism for loss of OH is about the same between daytime and nighttime. During the daytime OH production is ini tiated and maintained by sunlight, and the reaction of O({+1}D) with H{-2}O and reactions of HO{-2} with NO and with O{-3}  produce most tropospheric OH; however, the reaction of HO{-2} with O{-3} is the only significant source of nighttime OH. The reactions of OH with CO and with CH{-4} consume most tropospheric OH during daytime as well as nighttime. Second, this  thesis also presents a new method to further study the mechanism of OH by tracing a series of reactions activated by the key species and accounting for the effect on OH from each of the reactions. This method not only gives the conclusion that  on the global scale O{-3}, H{-2}O, and NO{-x} (NO+NO{-2}) produce the tropospheric OH which is mostly consumed by CO and CH{-4}, but also quantitatively gives the contribution of each of these key species to the tropospheric concentration of O H. The lifetime of a species represents the reactivity of a species. The lifetimes of OH and HO{-2} are illustrated and di scussed in this thesis. The lifetime of OH is very short. The vertically and diurnally averaged lifetimes are 1.2 second a t 45N and 2.3 seconds at 45S, which are about two orders of magnitude smaller than those of HO{-2}. Unlike OH, the lifet ime of HO{-2} shows a strong diurnal variation due to the strong diurnal variations of the concentrations of the species w hich remove tropospheric HO{-2}. The sensitivity of the tropospheric hydroxyl radicals to the heterogeneous process was te sted. It is shown that a strong heterogeneous process results in a much larger decrease of OH concentration in a polluted region at night than in a clean region during daytime. Finally the surface concentrations of OH over a wide range of clima te conditions were investigated. It is concluded that on average the OH concentration decreases only slightly from the las t glacial maximum (LGM, about 18,000 years ago) to the present despite the large changes of the concentrations of CO, CH{- 4}, O{-3}, and NO{-x}; however, the nighttime OH changes dramatically from the LGM to the present; the surface concentration of the nighttime OH at the LGM is about three times as large as that at the present.rcraft scenario. The emissions and "259^1^MacKay,Robert Malcolm^1990^6^The Oregon Graduate Institute One Dimensional Time-Dependent Radiative Convective Model #: Theory and Application^M.S.^Oregon Graduate Institute, Global Change Research Center^229^Thesis^^^Carbon, Climate, and V $egetation^^^^^^^485^^^^^^^^^^^^Environmental Science and Engineering, Applied Physics and Electrical Engineering^Khalil, M. Aslam K.^Rasmussen, R.A., and M.A.K. Khalil^DE-FG06-85ER60313^rom the ground, balloons, aircraft, rockets, and satelli &A^484^A time dependent one dimensional radiative convective model (1D RCM) is developed to study the sensitivity of the Ea 'rth's vertical temperature structure to variations in external and internal components of the climate system. Special emph (asis is given to the theory and development of the model so that it may be easily used and understood by others. The sensi )tivity of the Earth's surface temperature to variations in such parameters as the solar constant, surface albedo, cloud co *ver fraction, etc. is explored. The model developed is found to experience an approximate change in surface temperature of + 2.0 K for a doubling of atmospheric CO{-2} concentration (from 320 to 640 ppm). This compares favorably with other previo ,usly published results for similar models. The influence on mean global temperature of variations in the atmospheric conce -ntrations of CO{-2}, CH{-4}, N{-2}O, F11, and F12 over the past century is simulated with the model and compared with the .record of mean global temperature reconstructed from observations. In addition the effect of volcanic aerosols on the simu /lated record is explored. It is concluded that the OGI 1D RCM can serve as a valuable research tool in the future, for stu 0dying perturbations of the global average vertical thermal structure of the Earth-atmosphere system. It is also stressed that the 1D nature of the model is limited in that it offers no horizontal or seasonal resolution of the climate system.al 2260^1^Moraes,Francis^1992^6^Methane from a Destabilized Permafrost in a Warmer World^M.S.^Oregon Graduate Institute, Globa 3l Change Research Center^53^Thesis^^^Graduate Fellowships for Global Change^^^^^^^487^^^^^^^^^^^^Environmental Science and Engineering, Applied Physics and Electrical Engineering^Khalil, M. Aslam K.^Wohlpart, A.^DE-AC05-76OR00033^materials and 5A^486^A large amount of CH{-4} is sequestered in the upper layers of permafrost soils. This CH{-4} is likely to be release 6d if the soil thaws due to increased surface air temperature as predicted by most climate models. This thesis describes th 7e process of quantifying the CH{-4} release using available data from Alaskan soil cores, climate models, and a heat and g 8as transfer model. Based on this work, I conclude that permafrost will likely be a small though not negligible CH{-4} source in the future.ric ozone. Tropospheric chemistry involves a complex, nonlinear set of chemical reactions between atmos :261^1^Lu,Yu^1993^6^Model Calculations of Radiative Transfer and Tropospheric Chemistry^Ph.D.^Oregon Graduate Institute, Gl ;obal Change Research Center^244^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^489^^^^^^^^^^^^Environmental Science and Engineering, Applied Physics and Electrical Engineering^Khalil, M. Aslam K.^Rasmussen, R.A., and M.A.K. Khalil^DE-FG06 =A^488^The tropospheric chemistry of HO{-x}, NO{-y}, O{-x}, and CH{-i}O{-j} were studied with our time-dependent multiple o >ne-dimensional photochemical model. Besides its diurnal, vertical, seasonal, and latitudinal variations, the globally aver ?aged OH level may decrease by about 40% from ice ages to the present and about 10% from the pre-industrial era to the pres @ent. However, the averaged nighttime OH in ice ages is about three times as large as the current nighttime OH, 1.3x10{+4} Amolecules/cm{+3}, which is about two orders of magnitude smaller than the averaged daytime OH, 1.6x10{+6} molecules/cm{+3} B, at present. By tracing the reactions, which are initiated by the direct reactions of OH with CO and CH{-4}, the total ef Cfects of CH{-4} and CO were calculated. Atmospheric methane, along with its feedbacks, may remove as much as or more atmos Dpheric OH than carbon monoxide, although CO is widely accepted as the largest sink of the atmospheric OH. A detailed radia Etive transfer model was developed for various atmospheric conditions by including the optical properties and other physica Fl features of various types of clouds and aerosols. The model results indicates the variations of the synoptic and environ Gmental conditions in the lower atmospheric affect not only the actinic fluxes locally but also the radiation field in the Hupper atmosphere. Finally coupling the radiative transfer model with the photochemical model shows the effect of aerosols Ion OH chemistry becomes important only in the atmospheric boundary layer. The OH concentrations could drop significantly b Jelow a cloud but increase above the cloud compared to the OH levels in a clear atmosphere. The averaged OH level for the w Khole troposphere could be increased by low clouds but decreased by high clouds. More importantly, the increase of tropospheric OH by low clouds could be larger than that due to stratospheric O{-3} depletion.ession for the disturbance amplitude M262^1^Chaloupka,Kristin A^1994^6^Diagenetic Behavior of Arsenic in Amazon Shelf and Long Island Sound Sediments^M.S.^State N University of New York at Stony Brook^90^Thesis^^^Marine Transport^^^^^^^491^^^^^^^^^^^^Marine Sciences^Aller, Robert C.^Aller, R.C., J.K. Cochran, J.Y. Aller, and C. Lee^DE-FG02-92ER61464f energy dispersion from the forcing region and energy PA^490^Arsenic cycling in sediments is influenced by a variety of physical and chemical processes. Anthropogenic activities Q are also potentially important. In order to help elucidate major controls on diagenetic behavior of arsenic, vertical pro Rfiles of total dissolved and solid phase arsenic were measured in two physically distinct environments; the Amazon shelf a Snd Long Island Sound. The relative trends of arsenic distributions were similar in both study sites, with subsurface pore Twater maxima and surficial solid phase enrichment. In Amazon shelf sediments, these patterns reflect a strong redox associ Uation with iron whereby oxidized arsenic is adsorbed onto iron oxyhydroxides in surface sediments, which is then subsequen Vtly reduced and dissolved upon burial in the sub-oxic zone. Upward diffusion within the sediment is followed by readsorpti Won or release to the water column. On the Amazon shelf, intense physical reworking of sediments often releases the dissolv Xed arsenic fraction to the water column. In contrast, loss of arsenic from sediments in Long Island Sound does not reflect Y an energetic environment. Instead, it is linked to annual fluctuations in temperature and organic carbon inputs which, wh Zen high, deplete the oxygenated zone within the sediment, and result in an upward shift in redox processes. In addition to [ iron, arsenic is also closely coupled to the manganese and phosphate cycles in Long Island Sound; relationships which det \eriorate following a bloom event. Fluxes of dissolved arsenic from Long Island Sound sediment, calculated from pore water ]profiles during periods of elevated organic carbon deposition, are on the order of 0.025-0.634 mol/m{+2}/d, while the flu ^x from the solid phase into pore water is 1.42-11.5 mol/m{+2}/d. Disparity between these rates may reflect the fact that _the flux calculations exclude irrigation rates, adsorption onto additional mineral phases, physical reworking of sediments `, among other model assumptions. Pore water As concentrations in Amazon shelf sediments are an order of magnitude greater athan for sediments in Long Island Sound, and elevated concentrations extend several meters below the sediment surface. The bse expanded features are probably due to the combined effects of intense chemical weathering of riverine sediments and a t curbulent physical regime present on the shelf, both of which promote Fe cycling. Annual fluctuations in river flow result din increased physical mixing of the sediments during higher flow, and a greater abundance of benthic biota during lower ri ever flow, particularly away from the river mouth. This results in generally increasing arsenic pore water concentrations a fway from the river. Patterns of temporal variability are more difficult to discern, possibly due to differences in physica gl environments on the shelf. While some areas of the shelf are generally controlled by sediment transport processes, other areas are influenced more by benthic activity.aic stress model (ASM) correctly separates these normal stresses, which is i263^1^MacKay,Robert Malcolm^1994^6^The GCRC Two-Dimensional Zonally Averaged Statistical Dynamical Climate Model: Developm jent, Model Performance, and Climate Sensitivity^Ph.D.^Oregon Graduate Institute, Global Change Research Center^258^Dissert kation^^^Carbon, Climate, and Vegetation^^^^^^^493^^^^^^^^^^^^Environmental Science and Engineering, Applied Physics and Electrical Engineering^Khalil, M. Aslam K.^Rasmussen, R.A., and M.A.K. Khalil^DE-FG06-85ER60313^al Reynolds stresses that a mA^492^The two-dimensional statistical dynamical climate model that has recently been developed at the Global Change Resear nch Center and the Oregon Graduate Institute of Science & Technology (GCRC 2D) is presented and several new results obtaine od using the model are discussed. The model solves the 2-D primitive equations in finite difference form (mass continuity, pNewton's second law, and the first law of thermodynamics) for the prognostic variables zonal mean density, zonal mean velo qcity, zonal mean meridional velocity, and zonal mean temperature on a grid that has 18 nodes in latitude and 9 vertical no rdes (plus the surface). The equation of state, _p = rho RT_ and an assumed hydrostatic atmosphere, _delta p = -rho g delta s z_, are used to diagnostically calculate the zonal mean pressure and vertical velocity for each grid node, and the moistu tre balance equation is used to estimate the precipitation rate. The performance of the model at simulating the two-dimensi uonal temperature, zonal winds, and mass stream function is explored. The strengths and weaknesses of the model are highlig vhted and suggestions for future model improvements are given. The parameterization of the transient eddy fluxes of heat an wd momentum developed by Stone and Yao (1987 and 1990) are used with small modifications. These modifications are shown to xhelp the performance of the model at simulating the observed climate system as well an increase the model's computational ystability. Following earlier work that analyzed the response of the zonal wind fields predicted by three GCM simulations f zor a doubling of atmospheric CO{-2}, the response of the GCRC 2D model's zonal wind fields is also explored for the same e {xperiment. Unlike the GCM simulations, our 2D model results in distinct patterns of change. It is suggested that the obser |ved changes in zonal winds for the 2xCO{-2} experiment are related to the increase in the upper level temperature gradient }s predicted by our model and most climate models of adequate sophistication and resolution. We thus suggest that the same ~mechanism controlling the changes in zonal winds for the 2xCO{-2} experiment in our model also contributes to the simulated changes in zonal winds of the more complex GCMs.eavily dominated by the northern hemisphere, the natural source is fair 264^1^Moraes,Francis Perry,Jr^1994^6^The Global Change Research Center Atmospheric Chemistry Model^Ph.D.^Oregon Graduate I nstitute, Global Change Research Center^200^Dissertation^^^Graduate Fellowships for Global Change^^^^^^^495^^^^^^^^^^^^Env ironmental Science and Engineering, Applied Physics and Electrical Engineering^Khalil, M. Aslam K.^Wohlpart, A.^DE-AC05-76 A^494^A new 2.5-dimensional model of the chemistry of the troposphere has been developed. This model, the Global Change Re search Center Atmospheric Chemistry Model (GCRC-ACM), is a general tool for the study of the chemistry of the natural atmo sphere. It includes the O{-x}, HO{-x}, NO{-x}, and methane cycles. Each of these cycles has been included in the model suc h that they may be included or excluded from a given model run. This makes it possible to determine the importance of each cycle under different circumstances. The model includes a new, fast and accurate cloud model that allows the effects of r adiative changes due to clouds on atmospheric chemical processes to be assessed. The GCRC-ACM is used to assess the remova l of CH{-4}, CO, the methyl halides, HCFCs, HFCs, and CH{-3}CCl{-3}. The lifetime of CH{-3}CCL{-3} is 5.0 years and the gl obal tropospheric OH concentration is 9.910{+5} moleccm{+-3}. These values are lower and higher by roughly 10% than the values given by Prinn [personal communication]. This is due to the lack of non-methane hydrocarbon chemistry in the ACM. T he radiative effects of clouds on tropospheric HO are discussed. Globally, clouds increase HO by roughly 10%. Because clou ds increase HO values in some areas and decrease HO in other areas they have almost no net effect on the removal of trace gases which are well mixing within the troposphere. For gases that are not well mixed, such as CH{-3}I, the effect can be quite large.cycle of observed sea surface temperatures (SPEC SST), and two are coupled to a simple 50 m deep slab ocean m-85ER60313^1 x CO{2}) and doubled (2 x CO{2} amounts of atmospheric carbon dioxide. The 50 m slab ocean model acts as 265^1^Frolking,Stephen E^1993^6^Modeling Soil Climate Controls on the Exchange of Trace Gases Between the Terrestrial Bios phere and the Atmosphere^Ph.D.^University of New Hampshire^231^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^497^^^^^^^^^^^^Earth Sciences^Harris, Robert C.^Moore, Berrien^DE-FG02-90ER61083^gh southern latitudes in these mode runs show A^496^Soil temperature and moisture profiles (soil climate) have a strong influence on the rate of trace gas exchange betw een the terrestrial biosphere and the atmosphere through the controls exerted on microbial processes and the physical exch ange of gases. Principal controls of biological denitrification in mineral soils are the availability of carbon and nitrog en substrates and the soil anaerobic status. A process-oriented model of decomposition and denitrification in soils (DNDC) was modified to have a more detailed portrayal of these controls. In particular, a diffusive soil gas phase was added, al ong with a method for determining anaerobic and aerobic fractional volume within a soil profile. The model generally overe stimated N{-2}O fluxes when compared to field data from a sandy soil in Costa Rica, but captured the timing and shape of t he brief flux episodes. Several modeling shortcomings are discussed, including the nature of the carbon substrates and the nature and dynamics of soil anaerobic fractional volume. Methane flux from wetland soils is generally correlated with soi l temperature and depth to water table. A model of peat soil climate was developed and applied to a small poor fen in sout hern New Hampshire. Temperature profiles and ice depth are in good agreement with field data, but depth to water table is more problematic. Field-based flux correlations to soil temperature, depth to water table, and weighted recent precipitati on were developed. When used with the wetland soil climate model, much of the seasonal and shorter period flux variability was captured. The model was then driven by local weather data for 1926-1986; flux variability was dependent on both summe r season temperatures and summer precipitation patterns. It is estimated that a five-year field study would capture most o f the inter-annual variability. Sensitivity of northern peatland methane flux to climate variability was studied by combin ing data on flux rates, inundation areas. and summer temperature anomalies (1900-1986) for the eight major northern peatla nd regions. Spatial and temporal variability in summer temperature anomalies caused regional methane flux anomalies to be small, and not likely to provide a strong feedback to initial climate change.eologic inferences, the trend of those chang 266^1^Skole,David Lewis^1992^6^Measurement of Deforestation in the Brazilian Amazon Using Satellite Remote Sensing^Ph.D.^U niversity of New Hampshire^331^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^499^^^^^^^^^^^^Natural Resources^Aber, John^Moore, Berrien^DE-FG02-90ER61083egions was similar, precipitation results were more variable.","","Kutzbach, John E A^498^A clear understanding of the role of the biota in the global carbon cycle is limited by an absence of accurate measu rements of deforestation rates in the tropics. Thus study measures the rate and extent of deforestation in the Brazilian A mazon, a tropical forest biome approximately 5 x 10{+6} km{+2} in size and the largest extant tropical forest biome in the world. The study focuses on remote sensing measurements of deforestation rates and the area of secondary vegetation, but also utilizes tabular data to document deforestation when satellite data are not available. The analysis concludes: (1) Re gression analysis of SPOT, TM, and AVHRR measurements suggests that the AVHRR will greatly overestimate deforestation and be highly variable; the use of a brightness temperature threshold is highly sensitive and unreliable. The upward bias of A VHRR is a function of the density of deforestation. (2) An accurate measurement of deforestation requires Landsat TM data, and can be accomplished using low cost visual interpretation of photographic products at 1:250,000 scale, with accuracies within 10% if that obtained using digital image processing techniques employing supervised statistical classifiers. (3) S econdary growth in the Brazilian Amazon represents a large fraction of the total deforested area, and the abandonment of a gricultural land is an important land cover transition. Abandonment rates were 70-83% of clearing rates from primary fores ts. At any one point in time, approximately 30% of the deforested area is in some stage of abandonment, and quite likely n early all deforested land becomes abandoned after approximately 5 years. (4) Previous estimates of the total area deforest ed in the Amazon, as well as the rate of deforestation, have been too high by as much as 4-fold. A complete assessment of the entire Legal Amazon using over 200 Landsat images measures 251 x 10{+3} km{+2} deforestation as of 1988, or approximat ely 6% of the closed forests of the region. The average annual rate of deforestation between 1978 and 1988 was 18 x 10{+3} km{+2} yr{+-1}. These findings are important to carbon cycle research. They suggest the estimates of carbon emissions fro m the Amazon for the late 1980s have been too high, since the area of regrowth is large and rates of deforestation are lower than previously believed.vity factor Z{e} (mm{+6}/m{+3}) and cirrus ice content and ice crystal precipitation content 267^1^Vrsmarty,Charles Joseph^1991^6^Models of Macro-Scale Hydrology for Use in Global Change Research: Tests on Two Tro pical River Systems^Ph.D.^University of New Hampshire^255^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^501^^^^^^^^^^^^Earth Sciences^Moore, Berrien^Moore, Berrien^DE-FG02-90ER61083^ts. For vertically pointing operations, we find IWC = A^500^The subject of this dissertation is the terrestrial water cycle and development of tools to study the issue of globa l hydrologic change. A rationale is developed to study the water cycle at regional and continental scales using macro-scal e hydrology couples to Geographic Information Systems (GIS). A linked Water Balance/Water Transport Model (WBM/WTM) was co nstructed and tested as part of this research. The model was applied to two tropical river systems, the Amazon River in So uth America and the Zambezi River in southern Africa. The WBM/WTM is a distributed parameter model, operating at 0.5 (lat itude x longitude) spatial scale and with monthly timesteps. The WBM transforms spatially complex data on climate, vegetat ion, soils and topography into predictions of soil moisture, evapotranspiration and runoff. The WTM uses computed runoff, information on fluvial topology, linear transfer through river channels and a simple representation of floodplain storage to generate monthly discharge for any cell within a simulated catchment. For the Amazon, WBM/WTM results were checked agai nst established data sources and found to be in good agreement. The Zambezi simulation was more problematic. This study id entified and corrected errors in the precipitation, potential evapotranspiration, and soil water capacity data sets, and d emonstrated the importance of checking such calculations against reliable discharge data. Simulations with data from the A mazon and Zambezi River systems identified fluvial transport parameters which best matched observed discharge. Similar par ameters captured the dynamics of river flow in these strikingly different river systems. This suggests that large tropical rivers may have convergent properties that can be modeled using simple algorithms. This work produced a set of calibrated , macro-scale hydrology models for two large rivers prior to significant anthropogenic disturbance. Such simulations are p rerequisites to the study of hydrologic change. The major impacts of such change, from shifting land use, climate change, and water resources management, can be simulated using macro-scale hydrology models. The dissertation offers a strategy to accomplish this goal. experiment and a new bubble column apparatus. Gasliquid uptake studies have been completed for th 268^1^Bub,Frank Lee^1993^6^The Structure of Water Mass, Salt, and Temperature Transports Within Intermediate Depths of the Western Tropical Atlantic Ocean^Ph.D.^University of New Hampshire^222^Dissertation^^^Carbon, Climate, and Vegetation^^^^^^^503^^^^^^^^^^^^Earth Sciences^Brown, Wendell S.^Moore, Berrien^DE-FG02-90ER61083^he product of the Henry's law coeffici A^502^Water mass flow patterns within the 150-1300 m intermediate layer of the western tropical Atlantic were determined f rom observations during four 1990-1991 Pegasus velocity and CTD hydrographic surveys. Non-divergent flows were analyzed to determine transports. A survey-average 29 Sverdrups (1 Sv = 10{+6} m{+3}/s) of southern hemisphere water masses flowed no rthwestward across 44W near the equator as part of the subsurface South Equatorial Current (SEC). 21 Sv retroflected anti cyclonically around the Amazon Eddy (2N 45W) and flowed eastward toward the North Equatorial Undercurrent (NEUC). The ot her 8 Sv moved northwestward within a series of anticyclonic retroflection eddies which periodically separate from the Ama zon Eddy. 61 Sv of a northern/southern water mass mixture flowed southeastward across 9N as part of the North Equatorial Current (NEC) and bifurcated; 32 Sv turned anticyclonically northwestward, and 29 Sv turned cyclonically around a low (6N 44W), merged with the southern water, and flowed toward the NEUC. The 50 Sv NEUC, a mixture of mostly southern water, fl owed eastward into the interior. The remaining NEC and SEC branches blended to form a 40 Sv northwestward transport across 53W. These observed transports were generally about three times larger than the wind-driven equatorial and tropical gyre return transports (Mayer and Weisberg 1993); suggesting the existence of subgyre-scale recirculation eddies in the wester n tropics. One of the retroflection eddies was measured during September 1990. Its structure was approximated by a 300 km diameter cylinder which extended vertically through the surface and intermediate layers to 1300 m. During two other survey s, retroflection eddies were identified at the region's northwestern corner. Instantaneous transport associated with an ed dy which translated at 10 cm/s was about 30 Sv. Assuming three were generated each year, retroflection eddy translation co uld account for the 8 Sv alongshore flow through the region. According to water mass budgets, 21 Sv of northern water mass es were transformed by mixing within the region. Temperature-salinity relationships indicated this mixing effectively transports the cool, low salinity Antarctic Intermediate Water into the North Atlantic by as yet unknown pathways.odisperse d A^504^The objective of the Carbon Dioxide Information Center (CDIC) at Oak Ridge National Laboratory is to compile and dis tribute CO{-2}-related information under systematic quality control to international researchers and policy makers evaluat ing direct and indirect effects of increased CO{-2} levels. During a one-year internship beginning July 31, 1984, I helped compile, evaluate, and distribute numeric data and computer model packages. These packages provide well-documented, retri evable CO{-2} databases and computer models to researchers and help assure the long-term availability of documented CO{-2} data. In compiling six packages, I read CO{-2} research papers, wrote abstracts to document CO{-2} databases, wrote FORTR AN retrieval programs, developed graphics, and synthesized materials into a document format. This experience helped me to develop programming and technical writing skills and to expand my scientific knowledge. One package is included in this report as an example = Br or I) via X{2} + Y{+}  XY + Y{+}. The magnitude of the measured uptake and its functional A^506^As a result of increasing atmospheric CO{-2} concentrations and subsequent global temperature increases, the melting of polar ice sheets, mountain glaciers, and the thermal expansion of ocean water could lead to a rise in sea level. The c oastal erosion and inundation caused by this event could create agricultural, economic, demographic, and ecological proble ms along coastal zones. A preliminary Sea Shore Effects Analysis System (SEAS) data base was developed to answer questions on the effects of the global sea level rise. Resources potentially affected by a rise in sea level were identified, resul ting in the acquisition of eight data sets. Ten other sources of data were located, but are currently unavailable. The dat a are stored in SAS data sets. I propose that this information be analyzed using the Geographic Information System (GIS) o f the Environmental Sciences Division at Oak Ridge National Laboratory (ORNL) and the newly developed Digital Line Graph E levation Terrain Data of the U.S. Geological Survey. All SEAS data have longitude/latitude locational variables and, when merged with the terrain data on the GIS, they can be used for a detailed (e.g., 1m increment) analysis of the effects of s ea level rise. I recommend that development of the SEAS data base be continued with an emphasis on locating and obtaining additional data and using the GIS for analysis.eographic area where climatological ozone and temperature are a maximum. AOR00033^ three year January ozone and temperature averages for 198082 and 198991 yields differences that are similar to271^1^Comstock,Jonathan Paul^1985^6^Photosynthetic and Whole-Canopy Responses to Changing Plant Water status in Desert Shrub^M.S.^University of Utah^80^Thesis^^^Ecosystems Function and Response^^^^^^^509^^^^^^^^^^^^Biology^Ehleringer, James R.^Ehleringer, James R.^PCM 8208358hether changes in dynamics alone, represented by the geopotential height fields, can explA^508^The effects of changing plant water relations on plant carbon gain were studied in _Encelia frutescens_ (Gray) with respect to both physiological performance during periods of slowly declining plant water potential, and the phenology of leaf production and death associated with natural rainfall in a warm desert. Physiological studies of the photosynthetic responses of individual leaves to increasing water stress were carried out on potted plants at the University of Utah. Light-saturated CO{-2} assimilation rates decreased from 42.6 1.6 mol CO{-2} m{+-2} s{+-1} (x s.e.) to 1.7 1.7 mol CO{-2} m{+-2} s{+-1} as leaf water potentials decreased from -1.5 MPa to -4.0 MPa. This decline in net photosynthesis was show n to arise from both stomatal and nonstomatal effects, but not to equal degrees. The relative stomatal limitation, defined as the percent limitation in photosynthetic rate due to the presence of gas-phase diffusional barriers, increased from 11 2 (x s.e.) to 41 3% as water potentials became more negative. The importance of declining physiological capacity fo r photosynthesis in limiting whole-plant carbon gain was further studied in an experimental garden plot located in the Son oran Desert at the Phoenix Desert Botanic Garden. The production and longevity of leaves of _E. frutescens_ were followed under the natural rainfall regime during the summer and fall of 1984. The relationships between seasonally changing plant water status, extent of canopy development, and photosynthetic capacity per unit leaf area were determined. Maximum leaf life spans during a summer activity period were between 3 and 4 months, with the great majority living between 1 and 3 months. Leaf production occurred synchronously in well-defined cohorts triggered by precipitation events. Extensive leaf turnover occurred during the summer period even though the plants remained in continuous leaf. Turnover was most pronounced when precipitation triggered the production of new leaf cohorts. Five weeks were required for plants to reach maximum canopy development when renewed soil-water availability followed a prolonged drought. Photosynthetic capacity per unit leaf area recovered much sooner than total leaf area, and submaximal leaf area development was the major factor limiting whole-plant carbon gain during a leaf-flushing period lasting several weeks. As the soil began to dry out, physiological capacity declined more rapidly than leaf area, and became the primary limiting factor to whole plant carbon gain.sorption detector. A272^1^Comstock,Jonathan Paul^1989^6^Photosynthesis in Twigs^Ph.D.^University of Utah^132^Dissertation^^^Ecosystems Function and Response^^^^^^^511^^^^^^^^^^^^Biology^Ehleringer, James R.^Ehleringer, James R.^DE-FG02-86ER603995 year continuous A^510^Forty species from desert and adjacent riparian habitats were surveyed for twig photosynthetic activity. Photosynthetic capacity, as indicated by an increase in the net CO{-2} assimilation rate (A) in the light, was found in the twigs of all species. In most nondesert species, however, A was always negative. A was positive in the twigs of many desert species, which also exhibited specialized anatomies. The phenology and assimilation rates of leaves and twigs capable of positive net uptake were followed for one year. Both leaf and twig cohorts reached maximum values of surface area development and A in spring. The degree of drought related dieback during summer varied among species for both leaves and twigs, but when  A was positive in twigs, they were often more drought resistant than leaves of that same species. A detailed comparison wa!s made of leaves and twigs in a desert species with positive net photosynthetic twigs, _Hymenoclea salsola_. Leaves had hi"gher values of A and intercellular CO{-2} (c{-i}) than twigs when plants were well watered, and this may have been due to #greater anatomical specialization in the leaves. When the twigs of a given species did not have high stomatal densities an$d conductances, they always operated in the light with c{-i} above ambient and A negative. As leaf size increased among sp%ecies, twig respiration rates and gross photosynthetic rates increased. When twig respiration rates were high, photosynthe&tic nitrogen-use-efficiency may have been maximized by having twigs recycle endogenous CO{-2} at high c{-i}, and only leaves engaging in positive net uptake at c{-i} below ambient.3} were also investigated as apart of the Pacific Sulfur Inves(273^1^Donovan,Lisa Alayne^1992^6^A _Chrysothamnus_ Affair: Surviving and Developing Roots in Utah^Ph.D.^University of Utah)^144^Dissertation^^^Ecosystems Function and Response^^^^^^^513^^^^^^^^^^^^Biology^Ehleringer, James R.^Ehleringer, James R.^DE-FG02-89ER60775 and Nancy A. Marley","W31109ENG38, W7405ENG36","Atmospheric Chemistry" "Zieman, Jonathan J","+A^512^Water limits plant establishment and productivity in many arid and semi-arid habitats. This study investigated patte,rns of water-use characters in natural populations, and the relationships among water-use characters, growth and survival.- The study concentrated on _Chrysothamnus nauseosus_, commonly known as rubber rabbitbrush, and emphasized differences bet.ween juveniles (smaller establishing plants), and adults (larger reproductively mature plants). Juveniles were found to di/ffer from adults not only in size and rates of mortality, but also in their water status (xylem pressure potentials), rate0s of gas exchange (photosynthesis and stomatal conductance) and water-use efficiency (WUE, ratio of photosynthetic carbon 1gain to transpirational water loss). The differences were due, in part, to soil moisture availability, with shallow rooted2 juveniles being more water stressed and more dependent on moisture from summer rain. Summer drought resulted in high rate3s of seedling mortality for _C. nauseosus_, but larger seedlings and juveniles were more likely to survive the drought. Th4ough small plants were more water stress than large plants during each summer, they had lower WUE throughout the season, b5ased on measurements of instantaneous gas exchanges and of leaf carbon isotope discrimination (delta). This negative relat6ionship between delta and plant size in the natural population, as well as temporal shifts in delta found under controlled7 environment conditions, suggested that there was a developmental component to variation in WUE in addition to environment8ally induced variation. Quantitative genetic analysis indicated that there was also genetic variation for delta, though th9e estimates were relatively low, and hence some potential for genetic differentiation in delta in response to natural sele:ction. For _C. nauseosus_, lower WUE (higher delta) was not necessarily associated with greater biomass accumulation and g;rowth,and both photosynthetic capacity and stomatal limitation appeared to contribute to the variation in the relationship< between delta and growth. Though there were stable differences between juveniles and adults for water-use characters, and in particular WUE, the functional significance of these differences remains unknown.important regional and seasonal deta>274^1^Hesla,Bret^1984^6^The Implications of Spatial Variations in Adult Performance for the Distribution Patterns of Two P?erennial Halophytes in Tooele Valley, Utah^M.S.^University of Utah^63^Thesis^^^Ecosystems Function and Response^^^^^^^515^^^^^^^^^^^^Biology^Ehleringer, James R.^Ehleringer, James R.^PCM 8208358 OSU CGCM (in years 1120 of a 20year control inAA^514^The perennials _Allenrolfea occidentalis_ (Wats.) Kuntze and _Sarcobatus vermiculatus_ (Hook.) Torr. dominate two adBjacent shrub communities in many saline valleys of the Great Basin. In Tooele Valley, the populations of each species are Clargely restricted to within the communities they dominate, although rate individuals may be found within each adjacent coDmmunity. In order to gain insight into the factors limiting these populations at their edges, spatial variations in severaEl indices of adult performance were compared with spatial variations in population density, as well as with variations in Fthe soil environment. The lower edge of the _Allenrolfea_ population coincided with the bare mud flats of the valley centeGr. The gradual decline in density (linear cover of hummocks) toward this edge was paralleled by a significant decline in tHhe length, stomatal conductance, and reproduction (flowering frequency) of active twigs, the latter reaching zero at the eIdge. Since no other species occurred there, the decline in performance was probably a response to environmental changes. IJndeed, these performance indices were significantly correlated with both the depth to the water table and the salinity of Kthe water table. The lower edge of the _Sarcobatus_ population roughly coincided with the sharp ecotone between the _SarcoLbatus_- and _Allenrolfea_-dominated communities. Shrub density (#/m{+2}) dropped sharply at the lower edge (across the ecoMtone). Also declining toward this lower edge were individual height, leaf biomass, stomatal conductance, daily transpiratiNon, water potential, and reproduction (the frequency of flowering individuals), the latter reaching zero at the edge. ThisO spatial variation was maintained throughout the season. The removal of perennial competitors (_Allenrolfea_ individuals wPithin 3 m) induced small increases in individual water status at the lower edge of the population, but failed to induce inQcreases in leaf biomass or reproduction. The abrupt changes in plant performance across the ecotone were associated with aRbrupt changes in many soil properties, including water table depth, soil water salinity, phosphorus content, organic carboSn content, and clay content. The salinity and water table differences were maintained throughout the season. The upper edgTe of the _Allenrolfea_ population coincided with the ecotone between the _Sarcobatus_- and _Allenrolfea_-dominated communiUties. Density peaked at the ecotone, dropping significantly at the upper edge. In contrast, the length, stomatal conductanVce, daily transpiration, and water potential of twigs reached a maximum at the upper edge. However, like hummock cover, reWproduction peaked at the ecotone, being very low at the upper edge of the population. The removal of perennial competitorsX slightly stimulated water relations, leaf biomass, and reproduction at all locations, but did not alter the spatial trendYs. Low adult reproduction may have kept densities low at the upper edge. Environmental variation may contribute to the spaZtial variations in biomass and water status, but not directly to the spatial variations in reproduction. The upper edge of[ the _Sarcobatus_ population coincided with the ecotone between the _Sarcobatus_ and grassland communities. Density declin\ed gradually across the _Sarcobatus_ population, then abruptly at the upper edge. In contrast, height and reproduction rea]ched a striking maximum at the upper edge of the population, suggesting that adult performance had little bearing on the low densities there.the biota in the past several decades. The HILDAmodel is compared with other models, and we find that_A^516^To fulfill one of my requirements for the degree of Master of Environmental Science at the Institute of Environmenta`l Sciences (IES), Miami University, Oxford, Ohio, I performed an internship at the Carbon Dioxide Information Center (CDICa) in Oak Ridge, Tennessee. I had two primary projects: producing a newsletter and preparing a computer demonstration of a bprogram management tool called Coordination, Control, and Communication (C{+3}) system for the Department of Energy's Carbcon Dioxide Research Division (CDRD). The newsletter, _CDIC Communications_, is distributed to more than 1900 carbon dioxidde (CO{-2}) researchers and policy makers in 47 countries to inform them of major CO{-2} issues and events. My responsibilieties included all aspects of producing _CDIC Communications_: writing a production schedule, writing or editing the articlfes, doing the layout, and ensuring that the newsletter was mailed by its deadline. Before I could prepare a demonstration gfor C{+3}, I had to learn about each of the components in the system. Then, I wrote drafts of the demonstration, which werhe discussed with the CDRD program managers. The final draft will be programmed on an IBM personal computer using the IBM "iPC Storyboard" software package. Overall, I believe that I had a successful internship. I attribute much of the success toj the skills that I developed and practiced in some of the IES core courses such as statistics and Environmental Methodologky and the Public Information courses such as technical writing and independent studies in news writing and newsletter analysis.s have been developed starting from a simple twodimensional glacier flowline model. Numerous additions have been mamhe enhancement of cloud condensation nuclei (CCN) in the vicinity of and within clouds. Firstly, when clouds form due to ennhancement although this explanation is far from satisfactory and precludes the observed CCN enhancement in clear moist layers above the cloud tops.he lesser known parameters in the computation scheme. The information gained from these sensitip276^1^Hattemer-Frey,Holly A^1986^6^An Internship with the Carbon Dioxide Information Center^M.En.^Miami University^50^Repoqrt^^^Information^^^^^^^519^^^^^^^^^^^^Institute of Environmental Sciences^Vankat, John L.^Farrell, Michael P.^DE-AC05-84OR21400 of ice masses can be tested to the best of our current knowledge.","glaciology,surging,sea level","Budd, W.F.","MetsA^518^To fulfill one of the requirements for a Master of Environmental Science degree from the Institute of Environmental tSciences (IES), Miami University, Oxford, Ohio, an internship with the Carbon Dioxide Information Center (CDIC) at Oak Riduge National Laboratory, Oak Ridge, Tennessee, which lasted from August 1, 1985, through July 31, 1986. My internship respovnsibilities included two primary research projects: 1) producing the climatic indices publication, and 2) evaluating the fweasibility of using computer-generated sound to analyze long-term climate data. The climatic indices publication conciselyx describes 35 prominent indices to help meet the information needs of researchers who are evaluating the effects of increaysed atmospheric carbon dioxide levels. Five major steps were involved in producing the publication: 1) compiling an extenszive collection of indices from nine climate subject areas; 2) determining citation totals for each reference included in t{he climatic indices bibliography; 3) writing descriptions of 35 prominent indices; 4) sending out surveys to climate resea|rchers and analyzing the results; and 5) completing the tasks associated with publishing the document. Using sound to anal}yze data is based on the premise that one can hear differences in data patterns more easily than one can perceive these di~fferences visually. Three objectives associated with this project included: 1) determining how CDIC could adapt this technique to analyze climate data; 2) identifying and purchasing the appropriate equipment necessary to establish a computer driven sound-generating system; and 3) outlining recommendations for using sound to analyze complex, multivariate data. Much of the success of my internship may be attributed much skills developed in IES core and area concentration courses and to the guidance and assistance provided by CDIC staff members.ional data. Both show the greenhouse effect has the maximum vA^610^In three consecutive years (1983, 1984, and 1985) soybeans (_Glycine max_ L. Merr. cv Bragg) were grown from seed to The plants were separated into components to determine dry matter accumulation and leaf area extension, and then analyzedy (i.e., [DIC]=[H{-2}CO{-3}*]). Uptake of protons by weak organic acid ions appear to be the cause of the measured differerameters (size, fetch, depth). Satellite observations of lake ice patterns could greatly enlarge the spatial network of dadA^127^(Bobbi will get), about 12 Wm{+2}. By using a onedimensional radiative code from the CCM1, the values of the gloA^200^(Bobbi will get) calculated to be 136 Wm{+2} for July 1987 and 125 Wm{+2} for January 1987. The model is also useA^125^(Bobbi will get)tributions of atmospheric constituents to the total greenhouse effect for clear sky conditions. Wat[A^618^The cyanobacteria-rice interaction in paddy rice fields contributes to the soil nitrogen required to grow a rice crouhigh dissolved organic content of these waters appears to alter the electrode response yielding pH values lower than the t90ER61017^isture content and its distribution. Clouds also play an important role in the climate system. Clouds absorb trmbers under subambient (160, 220, 280 mol mol{+-1}), ambient (330 mol mol{+-1}) and superambient (660, 990 mol mol{+-1}/A^614^The overall goal of this research was the development, implementation, and validation of a computer-based data acquihlpart, A.^DE-AC05-76OR00033use effect. We study the cloud longwave radiative forcing both using the model and the observA^600^Recent consumption of fossil fuels is expected to lead to a doubling of CO{-2} concentration by about 2050. This mayA^606^Atmospheric carbon dioxide (CO{-2}) concentration has been increasing for the past 100 years and may double by the ynd of closing earlier and opening later than average during the decade 1970-1980. Freezing degree-days had higher correlatA^538^GALE, a national and multi-institutional project to study the physical mechanisms causing the formation and development of winter storms, was centered around the eastern Carolinas along the east coast of the United States from 15 January to 15 March, 1986. Data from six moored buoys in the coastal waters off the Carolinas and two research vessels mostly stationed at the western boundary of the Gulf Stream (GS) were used to study air-sea interaction processes. Data selection for the period of 20 January to 13 February, 1986 included several cases of cold air outbreaks, cold front passages, coastal frontogenesis, and offshore cyclogenesis. Prevalence of non-neutral conditions during the entire time period of GALE necessitated the selection of an appropriate method to account for the diabatic effects for computing the surface fluxes from the routine surface GALE data. An Iterative Bulk Aerodynamic Method (IBAM) is compared with the eddy correlation- and energy dissipation method to obtain surface fluxes of momentum and heat during the non-neutral boundary layer conditions and high winds (~22 ms{+-1}). After the intercomparisons of IBAMs, the IBAM of Liu, _et al._ (1979) was selected as a good indirect bulk method to use with the GALE data sets. Fluxes of momentum and heat from the mesoscale network of buoys and ships show significant temporal- and spatial variations in the coastal waters and along the western boundary of the GS with the south to north and cross-stream gradients. Spatial and temporal variations of these fluxes depend on the formation, location, intensity, and path of large-scale disturbances. During GALE, the highest fluxes, as measured from research vessels and buoys, occurred off the coast of South Carolina where high wind speeds and air-sea temperature differences were recorded frequently. For example, a momentum flux of 1.03 NM{+-2} and a total heat flux of 1243 WM{+-2} with an air-sea temperature difference of about -22C in the vicinity of the highly baroclinic GS front were observed in this area during the offshore cyclogenesis with cold air outbreak on 27 January/ at 0900 UTC. A salient feature of the spatial variation across the western boundary of the GS front is the prevailing accelerating effect that causes large deviations in the surface fluxes. Time series data for the depth of Oceanic Mixed Layer (OML) from a stationary location during 26/0000 to 27 January/1100 UTC show the response of the depth of OML with a lag of about two hours to the modulations of surface fluxes induced by the synoptic-/mesoscale atmospheric disturbances. The range of variations of OML depth is from 50 to 76 m when the variations of momentum, sensible heat, and latent heat are from 0.15 to 1.03 NM{+-2}, 24 to 367 WM{+-2}, and 214 to 874 WM{+-2} respectively. OML observations are far less than those obtained using one-dimensional models and the comparison shows that the models do not work well at the western boundary of the GS front probably because of strong horizontal advection.ization 278^1^Alliss,Randall Jamil^1992^6^The Utilization of SSMI/I Data in the Analysis of Tropical and Extra-Tropical Cyclones^M.S.^North Carolina State University^143^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^541^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Raman, Sethu^091575-A-Q1(<0*0*0* because it may improve the accuA^540^Recently, remote sensing of tropical and extra-tropical storms has been enhanced via data from the Special Sensor Microwave/Imager (SSM/I) launched by the Defense Meteorological Satellite Program (DMSP) in June 1987. Data obtained from SSM/I was analyzed and used to infer important meteorological parameters of Hurricanes Hugo (1989) and Florence (1988) as well as a mid-latitude cyclone which developed during Intensive Observational Period (IOP)-4 of the Experiment on Rapidly Intensifying Cyclones over the Atlantic (ERICA). These parameters include rainfall rates, integrated water vapor, marine surface wind speeds and 85 Gigahertz brightness temperatures used for center fixing the tropical cyclones. In this study, the utility of the SSM/I as a supplemental source of data in tropical and extra-tropical cyclones is evaluated. Results indicate that increases in SSM/I derived total latent heat release and increases in heavier rainfall rates near the center are associated with the intensification of both Hugo and Florence. SSM/I winds give a good description of the surface wind field of both Florence and the IOP-4 storm, outside areas of deep convection. SSM/I integrated water vapor is found to be particularly useful in locating the surface fronts associated with the IOP-4 cyclone. In addition, storm structure characteristics inferred from SSM/I of the ERICA IOP-4 storm compare well with the numerical results produced by the Naval Research Laboratory mesoscale model. Because SSM/I parameters were useful in observing the structure of these storms and compared well with in situ observations and model simulations, the applications described herein could be valuable in augmenting current analysis techniques of tropical and extra-tropical cyclones.2. After dissection, the number of primordia was counted279^1^Baik,Jong-Jin^1989^6^Tropical Cyclone Simulations with the Betts Convective Adjustment Scheme^Ph.D.^North Carolina State University^159^Dissertation^^^Marine Transport^^^^^^^543^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Pietrafesa, Leonard J.^DE-AS09-76EV00902uardt. Length of T3 and T10 apices was significantly (p<0.05) enhanced by 550 A^542^A new convective adjustment scheme proposed by Betts (1986) is incorporated into a tropical cyclone model. The convective parameterization scheme adjusts the local temperature and moisture structures towards the observed quasi-equilibrium thermodynamic state and includes non-precipitating shallow convection as well as deep convection. The numerical model used for this study is an axisymmetric, primitive equation, hydrostatic, finite difference model with 15 vertical layers and a horizontal resolution of 20 km. The model domain covers 1000 km and the spectral radiation boundary condition, which uses a different gravity wave speed for each vertical mode, is implemented in the model. It is shown that the convective scheme is capable of simulating the developing, rapidly intensifying and mature stages of a tropical cyclone from a weak vortex. During the early developing stage, the latent heat release is from the convective parameterization, but at the mature stage the latent heat release is mainly due to the grid-scale phase change. It is demonstrated that the increasing inertial stability and symmetric instability near the radius of the maximum wind in the lower troposphere can play important roles in the rapid intensification of the storm. For comparison, an experiment is conducted with the parameterized convection excluded, leaving only the grid-scale condensation and evaporation. The results show that the development of a tropical cyclone can be modeled with crude grid-scale condensation and evaporation processes for the 20 km horizontal resolution similar to other studies. However, the storm with the explicit convective latent heat release is considerably less intense than that with the parameterized convective latent heat release. The sensitivity of the model storm evolution to the convective adjustment parameters is investigated. These results show that the model storm develops earlier as the adjustment time scale becomes small and as the stability weight on the moist adiabat in the lower atmosphere is increased. The model storm evolution is very sensitive to variations in the saturation pressure departure at the lowest model integer level and the storm at the mature stage has a lower central pressure as the magnitude of the saturation pressure departure is increased. The adjustment parameters affect the grid-scale precipitation as well as the convective precipitation and the precipitation is especially sensitive to changes in the saturation pressure departure. Sensitivity of the model to variations in the sea surface temperature, latitude, initial vortex amplitude, initial moisture distribution and radiation is studied. The results of the numerical simulations are similar to previous studied. Sensitivity studies with various horizontal resolutions show that the subgrid-scale heating becomes a larger fraction of the total heating as the horizontal grid size is increased. The role of shallow convection in the tropical cyclone development is investigated. The simulation with both deep and shallow convection results in earlier development of the storm than that without shallow convection, but the intensity at the mature stage is similar in both cases. Finally, comparison of the Betts deep convective adjustment scheme with the Kuo convective parameterization is made. The result shows that the storm with the Kuo scheme intensifies earlier than the storm with the Betts scheme.contribute significantly to the total radiative forcing. Increase in CH{4} may lead to increas280^1^Byun,Dae-Won^1983^6^A Two-Dimensional Mesoscale Numerical Model of St. Louis Urban Mixed Layer^M.S.^North Carolina State University^216^Thesis^^^Marine Transport^^^^^^^545^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Arya, S.P.S.^Pietrafesa, Leonard J.^DE-FG09-85ER60376ospheric O{3} increase may decrease the CH{4} direct forcing by 30% at middle latiA^544^An urban boundary layer (UBL) is characterized by a smaller surface albedo than rural, large sensible heat flux due to the urban surface medium and small moisture availability, inhomogeneity of the surroundings, additional anthropogenic heat and considerably large surface roughness attributed to buildings and man made structures. A horizontal two dimensional numerical UBL model of St. Louis., which takes into account above differences of the urban from the rural, is developed based on the mixed layer assumption. For numerical integration, the time splitting technique is used in which the system is decomposed into an adjustment stage, a flux exchange stage and an advection stage. A cubic spline upstream advection scheme, which allows better choice of smoothing and boundary conditions than Mahrer and Pielke's (1978), is tested and utilized. The land use differences over the metropolitan area are characterized by the different proportions of the concrete and grassy soil surfaces. The thermal parameters of the vegetated soil are parameterized in terms of surface soil moisture content. From the homogeneous case studies. distinct urban and rural patterns of surface energy budget, which are typical of some observational studies, are obtained. It suggests that the simplification is successful in simulating the effects of different land use types on the atmosphere. Dynamics of a dome shaped model urban mixed layer is studied with the stationary balanced wind. It seems that the balanced wind can explain some important flow perturbations due to the urban heat island. Numerical simulation of the daytime boundary layer of St. Louis, Mo. on August 18, 1976, show some favorable results. The simulated wind field shows a heat island-related weak convergent area, complicated with the topographical effects, over the southwest side of the city in the morning. The model predicts surface temperature distributions similar to the observations showing a distinct surface urban heat island, although contour patterns differ from observations in detail. Downwind displacements of the mixed layer dome and urban plume phenomenon are simulated. However, influence of existing topography further complicated the mixed layer thickness patterns, especially in the morning. Further, the effects of only the urban heat island on the mixed layer evolution are studied by removing the topography in one simulation. The results of the run without topography show that the locations of local maxima and minima in mixed layer heights and temperatures coincide one another, suggesting existence of a direct relation between the two fields. In the morning, when the distinct mixed layer dome and high potential temperature region were present at the downwind side of the city, significant convergent flow is seen over that area. In the afternoon, the wind field is characterized by a nearly nondivergent and relatively homogeneous flow. The results here demonstrate the usefulness/potential of the vertically-integrated model for simulation of the clear day mixed layer. For such cases the present model can give increased understanding of the interrelationships between physical parameters determining the urban heat island phenomenon. For nighttime periods or morning and evening transition periods, a three-dimensional large eddy simulation model may be necessary..forcing induced by the observed ozone changes a281^1^Chanumalla,Neeraja Reddy^1992^6^A Study of Mesoscale Circulation and the Structure of the Baroclinic Boundary Layer over a Gulf Stream Filament^M.S.^North Carolina State University^148^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^547^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Raman, Sethu^091575-A-Q16%%%Y%%+%k%%%U  F FPFP4 ^&?u  x P"0 F uF0F#FP%HRPFdd FFM F]U$WV~ F FPFP4 ^&?tFFPFPFP FFFPFPFA^546^Observations obtained from aircraft, buoys, ships and vertical soundings made from 9-11 February, 1986 during the Genesis of Atlantic Lows Experiment (GALE) were used to study the mesoscale circulations and the mean and turbulent marine boundary layer structure over the cold coastal waters and the warm Gulf Stream. Different synoptic conditions prevailed on each day. The synoptic setting was characterized by prestorm conditions on 9 February, meso low development on 10 February and offshore cyclogenesis on 11 February. A Gulf Stream filament about 150 km long and 50 km wide was also formed during this period. Analysis of the data on 10 February indicates substantial increase in wind speed and change in direction across the filament up to a height of about 300 m. Northeasterly synoptic winds changed to a northwesterly direction, with win ds almost at right angles to the filament. This in combination with the effects of the horizontal temperature gradients be tween the coastal waters, the cold core of the filament and the Gulf Stream appears to have induced a mesoscale cyclonic c irculation. Wind speeds indicated a low level convergence over the filament. This mesoscale circulation and the convergenc e appears to have caused a meso-low over the filament which later developed into a mid-latitude cyclone when a mid-troposp heric trough advected into the region on 11 February. Turbulence profiles indicated that the similarity relations are valid during undisturbed weather. During disturbed conditions on 10 February and 11 February variances do not seem to follow the free convection relations. Conventional similarity relations with the height normalized by the boundary layer height did not exist during meso-low development and offshore cyclogenesis.282^1^Cione,Joseph Jerome^1992^6^The Effects of Surface Forcing on Mid-Atlantic Winter Cyclones^M.S.^North Carolina State University^120^Thesis^^^Marine Transport^^^^^^^549^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Pietrafesa, Leonard J.^DE-FG09-85ER60376IA^548^Mid-latitude cyclones develop off the Carolinas during winters and move north producing gale force winds, ice and heavy snow. It is believed that boundary layer and air-sea interaction processes are very important during the pre-cyclonic and development stages of these east coast storms. Due to the presence of the Gulf Stream, the marine boundary layer just offshore is highly baroclinic caused by warmer sea surface temperatures relative to the coastal waters. The offshore flow during cold air outbreak (CAO) periods initiates a strong heat flux distribution in the Western Atlantic Ocean that, over time, acts to vertically warm and moisten the atmosphere from below (Whittmann, 1982; Vukovich et al., 1991; Wayland and Raman, 1989; Holt and Raman, 1990). This airmass modification has been observed to substantially reduce regional stabilities over a time scale of 36 to 48 hours. This thesis looks into the effects the presence of the Gulf Stream off the Virginia and Carolina coastlines during the pre-storm environment potentially has on the intensification of coastal cyclones. The examination of nine years of data on the Gulf Stream position and east coast winter storms seems to indicate that the degree of low level baroclinicity and modification existing prior to a cyclonic event significantly affects the rate of cyclonic deepening off the mid-Atlantic coastline. 283^1^Gupton,Frank Marcus^1987^6^The Baroclinicity of the M{-2} Tide in the Georgia Bight^M.S.^North Carolina State Univer!sity^136^Thesis^^^Marine Transport^^^^^^^551^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Curtin, T.B.^Pietrafesa, Leonard J.^DE-AS09-76EV00902G#A^550^The importance of the M{-2} tide in the Georgia Bight is described. The tidal energy distribution of the Georgia Big$ht is discussed from two experiments, GABEX I (February - June 1980) and GABEX II (June - October 1981). Also the stabilit%y and coherency of the tidal particle motion is analyzed. Finally, the possible occurrence of an internal tidal wave using Fofonoff's (1969) criteria for the existence of an internal wave is shown using the GABEX I and GABEX II data.'284^1^Hendler,Albert H^1983^6^Cloud Condensation Nuclei from Urban-Industrial Sources and Their Impacts on Cloud Chemistry( and Microphysics^M.S.^North Carolina State University^96^Thesis^^^Atmospheric Sciences^^^^^^^553^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Saxena, Vinod K.^Saxena, Vinod K.^DE-AS02-78EV94965, DE-AS05-81EV10498*A^552^The results from two field experiments dealing with cloud-aerosol interactions in the urban environment are presente+d. In one of the experiments, real-time _in situ_ measurements of the cloud nuclei activation spectra over St. Louis, obta,ined as part of METROMEX ({uMetro}politan {uM}eteorological {uEx}periment), as used to identify industrial sources of clou-d condensation nuclei (CCN). The effluents of coal burning power plants are found to dominate the regional CCN production.. Other major industrial producers of CCN are found to be steel mills, copper and zinc smelters, and oil refineries. Since /St. Louis is a city of a large and diverse industrial base, these sources would likely dominate the anthropogenic CCN prod0uction in most urban-industrial areas. A natural source of CCN is also identified for the first time in the swampy marshla1nds northwest of St. Louis. In the second experiment, measurements of cloud nuclei activity, subcloud air chemistry, and c2loud water sulfate concentrations are used to investigate the contribution of the cloud nucleation process to the sulfate 3content of cloud water. Results show that in only one of four cases nucleation by subcloud sulfate aerosol can account for4 the entire sulfate content detected in cloud water samples. In all cases, substantial production of CCN is observed in the subcloud layer.6285^1^Hong,Xiaodong^1993^6^A Numerical Modeling Study of Vegetation as a Surface Forcing for Mesoscale Circulation and Clo7ud Formation^M.S.^North Carolina State University^98^Thesis^^^Atmospheric Radiation Measurement (ARM)^^^^^^^555^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Raman, Sethu^091575-A-Q19A^554^The effects of variable vegetation coverage as a surface forcing are examined by incorporating a vegetation paramete:rization into a mesoscale numerical model. Variable vegetation coverage leads to differential surface forcing which then c;reates mesoscale circulation. The mesoscale circulation and the interaction of the circulation with cloud production proces, with results compared to observations from the Boardman Regional Flux Experiment. The intensity of the vegetation breez?e circulation is directly related to the characteristics of the adjacent bare soil. There is a strong relationship between@ surface heat and moisture fluxes and the intensity of the vegetation breeze circulation. Greater sensible heat is transfeArred to the atmosphere over bare soil, while more soil moisture is transferred over the vegetated area than over the bare Bsoil area. Clouds induced by vegetation forcing are investigated by varying the atmospheric stability and moisture in the Cboundary layer and the atmosphere above it. The magnitude of the vertical velocity due to the thermally induced mesoscale Dcirculation decreases as the atmospheric stability increases. Two mesoscale circulation cells merge into one in the weak sEtability cases due to the smaller restoring force. Clouds are generated earlier for the less stable cases, but eventually Fdissipate because of enhanced mixing. In more stable cases, clouds are generated later in the simulation but persist longeGr as the vertical mixing is inhibited by the greater stability. Increased moisture in the lower layers strengthens the theHrmally induced mesoscale circulation by decreasing the stability. Increased moisture in the upper atmosphere leads to incrIeased cloud water. The scale of surface horizontal heating affecting cloud formation is also examined. One convective cellJ forms with narrow surface heating; as the scale of the heating increases, eventually two cells form. The depth of turbuleKnt mixing increases as the horizontal heating scale increases due to greater surface heating over the large horizontal areLa. When horizontal heating scale is narrow, increased evapotranspiration in the vegetated areas increases surface layer foMg or cloud water. The temperature, moisture and velocity components from the three-dimensional simulations are related to Nthe distribution of vegetation. The ground surface temperature is uniformly distributed over the irrigated area but is inhOomogeneous over the steppe area due to the penetration of the vegetation breeze. The colder air over the irrigated area doPes not penetrate over the steppe when the vegetation breeze opposes the ambient wind. A sharp horizontal moisture gradientQ is created between the two areas due to evapotranspiration from the vegetation and greater vertical mixing over the steppRe. Velocity perturbations at the interface between the steppe and irrigated land are largest when the vegetation breeze opposes the ambient wind.ʻ{~w~~||vy|yp{v}vpmmnntvsprsslprmtnnsn}rpgeggjfkkkfjkgmmlgllrgsuw:T286^1^Huang,Ching-Yuang^1990^6^A Mesoscale Planetary Boundary Layer Numerical Model for Simulations of Topographically IndUuced Circulations^Ph.D.^North Carolina State University^253^Dissertation^^^Marine Transport^^^^^^^557^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Pietrafesa, Leonard J.^DE-FG09-85ER60376ʾWA^556^A mesoscale planetary boundary layer (PBL) numerical model is developed to investigate airflow over complex topograpXhy. The model physics includes PBL turbulent transfer, atmospheric longwave and shortwave radiation, diurnal energy budgetYs over ground, cloud microphysics and subgrid cumulus parameterization. The model utilizes a new fourth order Crowley adveZction scheme which preserves phase and amplitude much better than other Crowley schemes. Turbulence closures using the tur[bulent kinetic energy (TKE) and dissipation () equations are investigated with the level 2.5 scheme of Mellor and Yamada \(1982) to better determine eddy diffusivities. One-dimensional (1-D) model results show that the PBL flows under various s]tability conditions are not significantly sensitive to the modified Blackadar's and Kolmogorov's eddy mixing length format^ions, although the latter yields excessively large mixing lengths in the entrainment region of the upper PBL. With the sam_e prognostic TKE equation, the model results show insensitivity of the 1-D flow to the details of diagnostic formulations `in the closures and to eddy Prandtl numbers. A 2-D model is used to simulate January 28 cold-air outbreak over the Gulf Staream region during the IOP-2 (Intensive Observation Period) of the 1986 Genesis of Atlantic Lows Experiment (GALE). The mobdeled 2-D circulation system is found to be sensitive to Prandtl number, in contrast to the 1-D model results. Prandtl numcber becomes increasingly important as the clouds begin to interact with the marine boundary layer (MBL). Using the E- clodsure, the model predicts the observed MBL structure that includes a low level jet west of the Gulf Stream warm core and a econstrained boundary layer height due to the middle-level stable layer. The results also indicate that the high cloud strefets observed downwind of the Gulf Stream are possible caused by the upper level baroclinic lee waves triggered by a densitgy mountain. The density mountain waves, however, become evanescent as the baroclinicity of the flow (with a larger Scorer hparameter) is removed, which agrees well with mountain wave theory. Two cases with 3-D idealized flow are also simulated fior the same GALE IOP. For the easterly onshore ambient flow, a confluence zone appears near the coastline in response to tjhe strong baroclinicity due to the Gulf Stream. This confluence zone is nearly parallel to the coastline and the SST isothkerms. With the increased coastal confluence, a shallow coastal front (below 2 km) begins to form. The northern part of thel front later encroaches inland as the coal air intensity over ground weakens due to onshore warm air advection. Stationarym rainbands are produced along the coastal front. For the northerly offshore ambient flow, the rainband first appears alongn the eastern edge of the Gulf Stream and moves slowly downstream. The fastest growth rate of the MBL-induced updrafts agreoes with the theory of conditional symmetric instability. The model is also applied to simulate the 3-D airflow past Taiwanp mountains. For both north-westerly and the south-westerly prevailing winds (with a Froude number of about 0.3), a mesoscaqle low pressure center occurs at the south-eastern (downstream) slopes of the steep mountains. The formation of meso-low mray be attributed to the combined effects of local confluence and adiabatic warming caused by the downslope wind. The role sof the PBL effects in changing the flow separation and stagnation points is found to be more important for the upstream fltow than the downstream flow. For the north-westerly flow, a downstream vortex pair can be generated near the two corners ouf the elongated island (with a smaller Rossby number). The geometry of the vortex pair is also determined by lateral mixinvg and thus is not greatly modified by the PBL destabilization. A strong downstream upslope wind is induced by the vorticesw and is further intensified by the PBL effects. This reversed flow results in greater precipitation than that produced by any upstream upslope flow.}~}~}{}DZ:?G2Qrd|}]gmy287^1^Leach,Martin^1994^6^The Interactive Role of Clouds and Radiative Transfer in Maintaining Atmospheric Circulation^Ph.zD.^North Carolina State University^150^Dissertation^^^Atmospheric Radiation Measurement (ARM)^^^^^^^559^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Raman, Sethu^Raman, Sethu^091575-A-Q1tnrprnrvwnmkfgpsmmkkjlnkmjpntnjpsv{:~|}}}y|y|{{|A^558^Radiative flux divergence is one of the principal physical forcings for atmospheric circulation. It affects the temp}erature, winds, cloud evolution and structure, and the water budget on all time and space scales. In this study, numerical~ models are used to study the effects of radiative transfers on a variety of atmospheric circulation systems on time scales from several hours to several days, and on space scales of about 10 kilometers to 10 thousand kilometers. Shortwave and longwave radiative transfer are added to a mesoscale model which includes detailed microphysics and turbulence closure schemes. This model is used to study three cases where radiative transfer plats a role in the structure of the atmosphere. The first is stratocumulus clouds that form in the wake of thunderstorms. Longwave radiative flux divergence at the top of the boundary layer maintains the cloud layer by cooling at cloud top, enhancing the inversion strength. Eventually, shortwave energy reaching the surface creates sufficient buoyancy to overcome the longwave forcing of the cloud layer, and the cloud dissipates. The same longwave forcing is responsible for the formation of boundary layer clouds in the second case studied, the coastal front. In that case, the presence of clouds also affects the horizontal heating of the atmosphere, as clouds effectively trap longwave energy below clouds, but also reflect shortwave energy, so that surface heating over land is less. The differences in radiative forcing changes the relative intensity of the thermal circulations that form over the Gulf Stream and at the coastline, with further feedback to the clouds, winds, temperature, and atmospheric water vapor. Finally, the third case was an examination of the effects of radiative transfer on low level cyclogenesis. Again, the longwave flux divergence at the top of the clouds maintained a cloud layer against the destructive force of mixing from below and entrainment from above. Once clouds form, horizontal thermal gradients lead to increased vorticity generation and a more intense circulation. A stronger circulation feedback to the cloud formation processes and water budget results. Finally, radiative transfer was added to a numerical weather prediction model to study the Indian summer monsoon. The length and time scales in this study were much longer, covering a 180 degree longitude by 90 degree latitude domain for 10 day forecasts. The conclusions however were remarkably similar to those from the smaller model. Radiative transfer maintains the strengths and structure of the components of the monsoon circulation system with feedback to cloud and precipitation processes.kQ_|t@J=`pI:E8EZ`0:0jY]8G?Oetus`=288^1^Lee,Jae Chul^1989^6^Circulation in the Vicinity of the Shelf/Slope Front in the Mid-Atlantic Bight^Ph.D.^North Carolina State University^106^Dissertation^^^Marine Transport^^^^^^^561^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Pietrafesa, Leonard J.^Pietrafesa, Leonard J.^DE-AS09-76EV00902tecmfJym_{uu~kwj}wELO8@jt}s@02cT2E@4QL44]{A^560^Subtidal variability of the shelf circulation in the Mid-Atlantic Bight was studied using a set of meteorological, coastal sea level, current velocity, temperature, salinity, chlorophyll content and light attenuation data obtained principally from a fixed array of SEEP-I moorings deployed from 16 February to 11 April 1984. A simple theoretical model with linear bottom friction and oscillating wind stress was developed in order to explain the phase relations between wind forcing and shelf circulation. The mean alongshelf current is in the downshelf direction. The vertical gradient of the alongshelf velocity (v{-z}) is relatively small at the inner stations and greater at the outer stations due to the stronger horizontal density gradient (rho{-x}) in the vicinity of the shelf/slope front. In effect, the time series of v{-z} at the outer stations and rho{-x} show high visual correlation. The mean cross-shelf circulation consists of onshore motion at the upper level and offshore flow near the bottom. An event which links onshore motions occurring at 84 meters depth in 124 meters of water and ridging of the frontal interface as predicted by Ou (1984) was observed. At the foot of the front, the temperature fluctuation is highly correlated with net displacement of cross-shelf flow. Phase lags of the alongshelf current in response to the longshore component of wind stress are found to be between 45 and 90 in the band of synoptic scale forcing corresponding to about 24 hours. A frictional adjustment time scale of about 40 hours in 100 m is obtained empirically by the application of a linear bottom stress model to the observed phases.mnglljfptcuyt~:w~vw}|mvt~v{{tstttsyRLr|}289^1^Liao,Nien-Tsun^1992^6^Spectral Analysis and Model Investigation of the Wind-Driven Midshelf Water Response from Cape Canaveral to Cape Fear During GABEX II^Ph.D.^North Carolina State University^156^Dissertation^^^Marine Transport^^^^^^^563^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Janowitz, Gerald S.^Pietrafesa, Leonard J.^DE-AS09-76EV00902w}A^562^The subtidal frequency responses of coastal sea level and alongshore currents to atmospheric forcing in the midshelf region between Cape Canaveral and Cape Fear is studied using data gathered during the GABEX II experiment, May 13 to October 15, 1981. It is found that wind field at synoptic period band (3-14 day) in the study area is well organized and propagates southward. In this highly barotropic region, it is also found that coastal seal level and current fluctuations are dominated by the response to the local wind forcing. The data indicate the lack of coastal trapped waves (CTWs) at 3-14 day period band although the phase speed in the alongshore current fluctuations at long period band (8-14 day) is 1.85 m s{+-1} with 87.4% of first mode fraction. A numerical model for coastal forced and free waves with realistic stratification and bottom topography is applied. The dispersion curves of first three modes for the barotropic and stratified cases at each single transect are obtained. It is found that the first mode long CTWs are highly barotropic, which is consistent with the large values of energy diagnostic R of these waves. The space-averaged phase speed of first mode long CTWs is 3.85 m s{+-1}, and wave motions noted from alongshore current fluctuations are not CTWs. With the aid of frequency response function, a comparison between the empirical observation and the theoretical model response is undertaken. In the 3-6 day period band, the model response and frequency response of alongshore current provide reasonable fit in magnitude with relatively uniform phase lags although there is remote response component due to the alongshore pressure gradient produced elsewhere. This suggests that the free-wave resonant response is less in this period band. At 8-14 day period band, the remote response of alongshore current is small relative to the local response component, and it is hard to give rise to the CTWs. Moreover, the frictional decay time T{-f} is short relative to the period of possible CTWs at this long period band, and the remotely induced energy is rapidly damped out in this broad and shallow continental shelf region. The linear bottom resistance coefficient r in the midshelf region along each single cross-shelf transect is also determined by approaching the model response to the frequency response in magnitude and 3-6 day period band. And, they are 0.03, 0.05, 0.055, 0.08, and 0.015 cm s{+-1} along the different transects with the values generally increase toward the north corresponding to the increasing width of continental shelf.ɺ{}||v|tu{yvv{{~vtywruyurvmsmkltllt290^1^Lin,Guoqing^1992^6^A Numerical Model of the Hydrodynamics of the Albemarle-Pamlico Croatan Sounds System, North Carolina^M.S.^North Carolina State University^118^Thesis^^^Marine Transport^^^^^^^565^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Pietrafesa, Leonard J.^Pietrafesa, Leonard J.^DE-FG09-85ER60376A^564^A linear, barotropic, three-dimensional, time-dependent, constant eddy viscosity model is developed for the entire Albemarle-Pamlico-Croatan sounds system. The study first analyzes the scales of time, velocity, and water level fluctuation of the flow field in the system. Analytical solutions under steady state are obtained to gain physical insight into the water motions. The factors influencing the flow field, e.g., wind stress, river discharge, tidal effect. eddy viscosity, bottom friction, and Coriolis effect are examined in terms of their relative importance. The finite difference method is used to numerically solve the time-dependent governing equations. The numerical model incorporates a spatially and temporally varying atmospheric wind stress, a stress bottom condition, river discharges, and tidal exchanges as boundary conditions. The bottom topography is incorporated into the model by utilizing a -coordinate. The model is verified using the results of field measurements within the sounds system. Several case runs of the model show that the flow field in Pamlico Sound is dynamically coupled with that in Albemarle Sound via restricted flow through Croatan Sound. The sounds system fully responds to wind action in a period of about 6 hours for north/south direction and about 4 hours for east/west direction. The water parcels throughout the water column in Croatan Sound flow in the direction of a constant north/south wind for the first 14 hours after wind onset. The circulation response reaches quasi-steady state condition for a constant wind forcing in a period of about 24 hours for the north/south wind and about 18 hours for the east/west wind. The model is used to run a representative case of measured time series of wind stresses in three months of winter, which is believed to be the peak recruitment period for five commercially important estuarine-dependent, migratory marine species to the sounds system. The results support the hypothesis that the dynamic coupling of Croatan Sound is unfavorable for the larval recruitment into Albemarle Sound. The model can also be used to forecast the water level fluctuations and to compute the water exchange rate of embayments along the periphery of the sounds system. The model results of the tropical storm surge simulation are satisfactory.@:QRZy]@kI8fmfyd~dD=D@U4=E\]UZR_JOI]_]LLTRrRV=?]ccud?UZg\_e_rgGQ]nk_ZITLeJY291^1^McCann,Michael Paul^1984^6^Physical Processes Influencing Temperature and Salinity on the North Carolina Cape Shoals^M.S.^North Carolina State University^138^Thesis^^^Marine Transport^^^^^^^567^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Pietrafesa, Leonard J.^Pietrafesa, Leonard J.^DE-AS09-76EV00902rrwyuuklruclDGdYD2,.0.:.0?U_DUTQ`Q:4?JD4Q428=A^566^Cross-spectral analysis and a heat budget are used to relate atmospheric and river runoff data with seven years of daily surface temperature and salinity on the North Carolina continental shelf. Salinity on Diamond Shoals is highly correlated with alongshore wind stress implying wind driven advection of the front between Virginia Coastal Water and Carolina Coastal Water. In the presence of strong horizontal and vertical temperature gradients, temperature at Diamond Shoals quickly responds to cross-shelf winds. At Frying Pan Shoals, the plume of the Cape Fear River is detected when winds blow seaward. Atmospheric fluxes primarily control the cycle of heating and cooling at Frying Pan Shoals, but advection of heat buffers the water temperature in the winter and summer.{}|w}vwvyurptnpyjsnkkfll\]Z\_TRZVl2pdccg__U_Rvwwtyprps~\Y?E8292^1^Purba,Mulia^1984^6^A Parametric Evaluation of Observations in the Georgia Bight, March - May, 1980^Ph.D.^North Carolina State University^159^Dissertation^^^Marine Transport^^^^^^^569^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Pietrafesa, Leonard J., and Gerald S. Janowitz^Pietrafesa, Leonard J.^DE-AS09-76EV00902ÿŶ|ypyuy{w~}~~A^568^An evaluation of the terms that appear in the equations governing the momentum balance have been made by using current meter data collected during a four month experiment (Feb. - June 1980) conducted in the Georgia Bight. Supplemental data sets, such as those of coastal sea level and continental shelf, marine meteorology also are utilized. Time and space difference approximations are used to estimate temporal rate of change and spatial gradients, respectively. Two sets of L-shaped mooring array triplets are chosen for this study. The results show that the diabathic (cross-shelf) momentum equation is basically geostrophic while the parabathic (alongshore) momentum balance is predominantly ageostrophic. Similar results are found for the case of temporally meaned momentum equations. However, the vertical Reynolds stress term is also important in the mean parabathic momentum balance. In the midshelf region evidence is found that subtidal frequency flow is influenced principally by local wind forcing. The geostrophic balance in the diabathic momentum equation could be best categorized as an Ekman frictional mechanism. The existence of the Florida-Georgia-South Carolina wall effectively causes a sea level drop (rise) in the events of northward (southward) winds, establishing an onshore (offshore) diabathic pressure gradient force, which is balanced by the resulting north (south)ward geostrophic interior flows. The spatial and temporal variability of wind events along the coast, particularly the alignment of the meteorological "high" and "lows" with the coast, causes sea level to drop (rise) differentially along the coast, establishing the parabathic pressure gradient. As a corollary parabathic currents vary accordingly. Consequently, the time derivative of these parabathic currents becomes important in the parabathic momentum equation, yielding an ageostrophic balance. The parabathic pressure gradient force is found to be directed in the same direction as the parabathic wind stress because of the alignment of the weather systems relative to the curved coastline.ý293^1^Ruggiero,Frank Harrison^1987^6^Experimental Studies of Clouds and Aerosols Along the Antarctic Coast^M.S.^North Carolina State University^64^Thesis^^^Atmospheric Sciences^^^^^^^571^^^^^^^^^^^^Marine, Earth and Atmospheric Sciences^Saxena, Vinod K.^Saxena, Vinod K.^DE-AS05-81EV10498A^570^Results of a study of Antarctic coastal stratus clouds over the Ross Ice Shelf are presented The pristine nature of the Antarctic atmosphere provides a natural laboratory to learn the microphysical reactions to anthropogenic pollutants and aerosols. Bimodal droplet size spectra and spectral broadening increasing with height were detected. This bimodality although contrary to classical growth theory may be explained by entrainment within the cloud. The supersaturation in these clouds are rather high due to limited competition for water vapor caused by low concentrations of cloud condensation nuclei (CCN). Cloud water samples were taken from the Antarctic coastal clouds and analyzed for their acidity and ion contents. The pH of the cloud water ranged from 4.9-6.2. Total SO{-4}{+=} concentration was found to increase with height inside the cloud although excess sulfate content showed a decrease with height. Average levels of total SO{-4}{+=} were found to be of the same magnitude as those in the regions surrounded by anthropogenic sources but NO{-3}{+-} concentration was much lower. Being devoid of influences from significant anthropogenic ground sources, Antarctic cloud water affords an unusual an