Arctic Tundra Ecosystems
Global Change Research Group
San Diego State University

Principal Investigator - Dr. Walter C. Oechel
Department of Biology
5500 Campanile Drive
San Diego, CA 92182
Phone: (619) 594-6613
Fax:  (619) 594-7831



SITE LOCATIONS
Barrow site (71° 21' 00.00" N : 156° 37' 18.53" W) is located adjacent to the National Oceanic & Atmospheric Administration's Climate Monitoring and Diagnostics Laboratory (NOAA-CMDL).  The area is composed of several different representative wet-moist coastal sedge tundra types.

Atqasuk site (70° 28' 10.6" N : 157° 24' 32.2" W) is located 100 km south of Barrow, Alaska, and adjacent to the native village of Atqasuk.  Soils are developed on aeolian sands of Quaternary age.  The site is comprised of a variety of moist-wet coastal sedge tundra, and moist-tussock tundra surfaces in the more well-drained upland.  

UPAD site (70° 16' 53.5" N : 148° 53' 05.4" W) is located on the Prudhoe Bay, Alaska, oilfield.  The vegetation is a mixture of moist and wet coastal sedge tundra.  

The three sites measure year-round CO2 and H2O fluxes and energy fluxes. 

INSTRUMENTATION
     The eddy correlation measurement system provides in situ 10Hz data of CO2, H2O,  sensible heat and latent heat fluxes using a three-dimensional Gill (R3) ultrasonic anemometer/thermometer with an open-path CO2/H2O (NOAA-ATDD) infrared analyzer.  These 10Hz data are then averaged every 30minutes to obtain half-hourly flux estimates of mass, momentum and energy.  Additional, meteorological variables such as net radiation, photosynthetically active radiation (PAR), ground heat flux, air temperature, relative humidity, soil temperature and precipitation are measured and stored as 30-min averages (precipitation as accumulated half hour totals).  

DATA FORMAT
Variable List (Symbols and Units)

The file is in ASCII comma -elimited text format. Missing values are represented by "-9999".  No data collected are represented by "N/A".


Disclaimer:
Data processed in 1999 have to be considered preliminary and these estimates could change considerably and without notice.  
Please contact us if you plan to use our data, and we reserve the right to co-authorship if deemed appropriate. 

Symbol
Description
Instrument
Unit

YY
Year



JD
Julian Day



TM
Time



Rn
Net Radiation
Q-7 (REBS)
W m-2

LE
Latent Heat Flux
ATDD/NOAA Open-Path IRGA
W m-2

H
Sensible Heat Flux
Sonic Anemometer (Gill inc)
W m-2

G_1
Soil Heat Flux
HFT-3 (REBS)
W m-2

G_2
Soil Heat Flux
HFT-3 (REBS)
W m-2

PAR
Photosynthetically Active Radiation
LI-190SB (LI-COR)
muE m-2 s-1

Air T
Air Temperature at 
HMP 35C (Vaisala) 
oC

Soil T1_0
Soil temperature at 0 cm
Type-T Thermocouple
oC

Soil T1_5
Soil temperature at -5 cm 
Type-T Thermocouple
oC

SoilT1_10
Soil temperature at -10cm 
Type-T Thermocouple
oC

Soil T2_0
Soil temperature at 0 cm
Type-T Thermocouple
oC

Soil T2_5
Soil temperature at -5 cm 
Type-T Thermocouple
oC

SoilT2_10
Soil temperature at -10cm 
Type-T Thermocouple
oC

RH
Relative Humidity
HMP 35C (Vaisala)
%

Rain
Precipitation
TE525  (Texas Electronics)
mm

WD
Wind Direction
Sonic Anemometer (Gill Inc.)
o (True)

WS
Wind Speed
Sonic Anemometer (Gill Inc.)
m s-1

u*
Friction Velocity
Sonic Anemometer (Gill Inc.)
m s-1

FCO2
CO2 Flux 
ATDD/NOAA Open-Path IRGA
mg m-2 s-1

FH2O
H2O Flux
ATDD/NOAA Open-Path IRGA
mg m-2 s-1