Howland flux and Environmental data
Main tower 45.20407° N, 68.74020° W

PI: David Hollinger
001-603-868-7673
davidh@hypatia.unh.edu

version "E"  1996-2002, September 2004

Guidelines for Use:

These data are subject to revision. Please check with the PI prior to
use in a publication.  These data are available subject to the AmeriFlux
"Fair Use" guidelines reproduced below.  These data represent thousands
of person-hours of work paid for by the USDA Forest Service and the US
Department of  Energy.  Please acknowledge our support as indicated
below.  

Authorship considerations when using Howland data: 

These data, especially the flux data, are the product of considerable time
and thought.  If you wish to use these data, here are our guidelines for
co-authorship by the Howland PI;

1) If you use only the meteorological data, please indicate the source 
of the data and the agencies responsible for supporting Howland.
Please provide us with a copy of your manuscript. Co-authorship not
necessary.
2) If your conclusions are based in whole or in part on an analysis of
Howland flux data, a co-authorship would be appropriate.  This includes
cross-site comparisons, analysis of resource use efficiencies, fitting 
of models, inferring fluxes from remote sensing data, etc.
3) Any questions, just call or email.

AmeriFlux Fair Use Rules: (by using the data you agree to these terms)

Please kindly inform the appropriate AmeriFlux scientist(s) of how you
are using the data and of any publication plans. Please acknowledge
the data source as a citation or in the acknowledgments if the data
are not yet published. If the AmeriFlux Principal Investigators (PIs)
feel that they should be acknowledged or offered participation as
authors, they will let you know and we assume that an agreement on such
matters will be reached before publishing and/or use of the data for
publication. If your work directly competes with the PI's analysis they
may ask that they have the opportunity to submit a manuscript before you
submit one that uses unpublished data. In addition, when publishing,
please acknowledge the agency that supported the research. Lastly,
we kindly request that those publishing papers using AmeriFlux data
provide preprints to the PIs providing the data and to the data archive
at the Carbon Dioxide Information Analysis Center (CDIAC).

Acknowledgement:

The Howland flux research was supported by the USDA Forest Service
Northern Global Change Program, the Office of Science (BER),
U.S. Department of Energy, through the Northeast Regional Center of
the National Institute for Global Environmental Change under Cooperative
Agreement No. DE-FC03-90ER61010, and by the Office of Science (BER),
U.S. Department of Energy, Interagency Agreement No. DE-AI02-00ER63028.

These data and the procedures used to produce them are described in the
publications listed below.  The fluxes have been corrected for low and
high frequency losses.

"Spatial and temporal variability in forest-atmosphere CO2 exchange"
(2004) DY Hollinger, J Aber, B Dail, EA Davidson, SM Goltz, H Hughes, 
MY Leclerc, JT Lee, AD Richardson, C Rodrigues, NA Scott, D Achuatavarier, 
and J Walsh. Global Change Biology, In Press.

"Seasonal patterns and environmental control of carbon dioxide and water
vapor exchange in an ecotonal boreal forest." DY Hollinger, Goltz SM,
Davidson EA, Lee JT, Tu K, Valentine HT (1999) Global Change Biology,
5, 891-902.

-999 indicates missing

Column name		description				units

JD			Julian day				days
Year
FCO2cumm_fill.25u*	cummulative "filled" CO2 flux		g C m-2
fillFCO2_.25u*		half-hour "filled" CO2 flux		umol CO2 m-2 s-1 
                                                                (nocturnal u* threshold of 0.25 m s-1)
FCO2			measured CO2 flux			umol CO2 m-2 s-1 
resp.25			measured or modeled nocturnal CO2	umol CO2 m-2 s-1 
H			measured sensible heat flux		W m-2
LE			measured latent heat flux		W m-2
Monin-Obuhkov length	stability parameter			m
Rn                      net radiation                           W m-2
PPT			precipitation				mm (may be inaccurate in the winter)
Tair			air temperature				degrees C
ubar			horizontal wind speed			m s-1
ustar			friction velocity			m s-1
winddir			wind direction				degrees azimuth
ea			vapor pressure				millibar
satdef			saturation deficit			millibar
PPFD			photosynthetically active photon flux	umol m-2 s-1
tairfill		"filled" air temperature		degrees C
tsoil5cmfill		"filled" soil temperature at 5 cm depth	degrees C


Additional data are available - contact the PI.