1. Field Data & Instrumentation
Faith Ann Heinsch
March 6, 2008

2. Fluxnet Towers, March 19, 2007
467 Sites, 46 Countries

3. Growth of Fluxnet – as of 09/30/2006

4. Distribution of Flux Towers by Land Cover – March 2007

5. Flux Tower Climate Relative to Global Climate – March 2007

6. Flux Towers

7. Network Towers

9. Micrometeorological data
Radiation
Incident PAR
Incoming Shortwave
Net Radiation
Air Temperatures
Daily Mean, Max, Min
Vapor Pressure
Relative Humidity or Actual Vapor Pressure
Soil Temperature and Heat Flux
Precipitation
Wind Speed/Direction

10. Solar Radiation Net Radiation
Photosynthetically Active Radiation (PAR)
Incoming Shortwave &
Downwelling Longwave
Radiation

11. Solar Radiation

12. Air Temperature, Relative Humidity
T & RH T

13. Soil Temperature & Moisture
Soil Moisture & Heat Flux

14. Precipitation

15. Wind Speed/Direction
3-D Sonic Anemometer
Traditional Anemometers

16. Eddy Covariance Flux data
CO2 Flux
H2O Flux
Vertical Wind Speed/Direction
Eddy covariance measurements basically give you the difference between the gas leaving the system and the gas entering the system. The actual amount (i.e., concentration) does NOT matter for calculations of NEE (net ecosystem exchange, μmol C m-2 s-1).

17. wind direction fetch 3-D Sonic Anemometer
As air parcel warms it becomes lighter than surrounding air and rises (updrafts).
Conversely, cool air is heavier and sinks (downdrafts).
Air enters tubing under a 0.5 l min-1 vacuum - splits into 2 pathways
direction determined by sonic anemometer
fetch

18. Eddy Covariance Flux Tower “Open” System

19. Eddy Covariance Flux Tower “Closed” System

21. Miscellaneous System Components
Towers - fetch

22. Data Loggers
CR10X
CR23X
Retired!

23. Power

24. Components
Yards & Yards of
Teflon Tubing
Teflon Valves
Teflon Filters

25. Inside the Box

26. Environmental Data Leaf-level Photosynthesis Soil Respiration
Leaf Area Index
Transpiration

27. Leaf/Soil CO2 Flux System

28. Leaf/Soil CO2 Flux System
CO2, H2O, light are set by user and controlled by system
Once conditions are stabilized, measurements begin
Measurement Mode
Open system design –[CO2] is steady-state
CO2/H2O gas exchange (rate of change within chamber [in – out]) and temperature parameters are measured

29. Leaf/Soil CO2 Flux System
Drawdown Mode
Air pumped through soda lime (CO2 scrubber) and back into chamber
Measurement Mode
When CO2 below set point, begins measuring time it takes to get to upper set point.
Flux is based on running average of rate of change in [CO2] with time.

30. Soil CO2 Flux System

31. Leaf Area Index

32. Leaf Area Index

33. Leaf Area Index – Gap Fraction Analysis
Digital camera NIKON Coolpix5000 with a NIKON
FC-E8 fisheye converter
Delta-T Hemiview System
e.g., Martens et al., Estimation of tree canopy leaf area index by gap fraction analysis, Forest Ecology and Management, 61:

34. Transpiration

35. Fluxnet Towers, March 19, 2007
467 Sites, 46 Countries