AmeriFlux Data and Site Comparison


Project


Coordinator: Dave Hollinger

Product: multi-authored manuscript


Where: Science/BioScience/?

Time Frame: 6 months


Timeline

Data Delivery: Mid/End November 1998 to Antoinette Brenkert or Eva Falge

1st Draft: End of December 1998 to all

Workshop: End of January 1999 in Oak Ridge


Participants (so far)

 

Site

State

PI

Ecosystem Type

Walker Branch

Tennessee

D Baldocchi

temperate deciduous forest

Harvard Forest

Massachusetts

SC Wofsy, JW Munger

temperate deciduous forest

WLEF/Park Falls

Wisconsin

P Bakwin

temperate/boreal forest

Howland Forest

Maine

DY Hollinger

boreal coniferous forest

Ponca City

Oklahoma

S Verma

crop (winter wheat)

Shidler

Oklahoma

S Verma

tallgrass prairie

Camp Borden

Ontario

J Fuentes

boreal deciduous forest

Metolius

Oregon

M Unsworth, B Law

temperate coniferous forest

North Boreas

Manitoba

SC Wofsy

boreal coniferous forest

Bondville

Illinois

T Meyers

crop (soybean, corn)

Little Washita

Oklahoma

T Meyers

rangeland


ALL AmeriFlux sites are welcome to participate in this synthesis effort. If you would like to participate please send
the prescribed data listed below to the persons mentioned above.

 

Key Questions

 

- Effect of abiotic and biotic factors on C fluxes across a gradient or network

- Construction of defensible sums

- Comparison of responses within and between biomes

- Comparison of responses to environmental factors

- Comparison of seasonal patterns

 

 

Data List

 

0) Climate Summary

 

Units

Annual

July

Air temperature

deg. C

(mean)

(mean)

Soil temperature

deg. C

(mean)

(mean)

Vapor pressure deficit of the air

kPa

(daytime mean)

(daytime mean)

Net Radiation

kJ m-2 yr-1 or kJ m-2 month-1

(sum)

(sum)

Precipitation

mm yr-1 or mm month-1

(sum)

(sum)

LAI (projected)

m2 m-2

(mean)

(mean)

1) Diurnal Data


for July 1996 and/or July 1997 and/or peak period

mean daily course and standard deviation (based on 30- or 60-minute values) of

 

 

Timestep

Time

hour (minutes as decimals)

End time of averaged time interval

Latent heat flux

LE

W m-2

Rate of vertical transfer of latent from measurements above the canopy (and corrected for latent heat storage in air layer ???)

Net radiation

Rn

W m-2

Net radiation as difference between the incoming and outgoing total radiation.

Net Ecosystem Exchange

NEE

µmol m-2 s-1

Rate of vertical transfer of CO2 calculated from measurements above the canopy and corrected for CO2 storage in canopy air layer and CO2 drift (if applicable)

Sensible heat flux

H

W m-2

Rate of vertical transfer of heat from measurements above the canopy (and corrected for heat storage in air layer and canopy biomass???)

Soil heat flux

G

W m-2

Averaged soil heat flux density

Photosynthetic Active Radiation

PAR

µmol m-2 s-1

PAR is the radiation in the 0.4-0.7 m m waveband.

Momentum

TAU

m2 s-2

Rate of vertical transfer of momentum

Air temperature

Ta

degrees C

Measured above the canopy

Relative humidity

Rh

%

Measured above the canopy

Soil temperature

Tscm

degrees C

Averaged temperature of the soil at different depths (cm for depth)

Precipitation

P

mm

Total precipitation during the observed time period

 

 

2) Daily Sums

Annual course of daily sums of NEE in units of g C m-2 day-1

Gap filling preferably using PAR, and Tair response; for instructions - if needed - see appendix.

 

3) Responses and Nighttime Fluxes

 

for two weeks during peak vegetation period and preferred wind direction

30- or 60-minute values of the variables listed under 1) Diurnal Data,

additional variables:

 

Wind direction

WD

degrees

Wind direction clockwise from North

Sky conditions

Sky

-

Indicator for cloudy/clear conditions:

0 (clear) to 1 (cloudy)