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Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley

Applications of eddy covariance measurements, Part 1: Lecture on Analyzing and Interpreting CO 2 Flux Measurements. Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley. CarboEurope Summer Course, 2006 Namur, Belgium. Outline. Philosophy/Background Processing

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Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley

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  1. Applications of eddy covariance measurements, Part 1:Lecture on Analyzing and Interpreting CO2 Flux Measurements Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley CarboEurope Summer Course, 2006 Namur, Belgium

  2. Outline • Philosophy/Background • Processing • Time Series Analysis • Diurnal • Seasonal • Interannual • Flux Partitioning • Canopy photosynthesis • Ecosystem Respiration • Processes • Photosynthesis • f(T,PAR, LAI, soil moisture) • Respiration • f(photosynthesis, soil C &N, T, soil moisture, growth) • Functional Type • Disturbance • Space • Cross-Site Analyzes

  3. Philosophy/Background • Philosophy • What, How, Why, Will be? • BioPhysical Processes • Meteorology/Microclimate • Light, temperature, wind, humidity, pressure • Vegetation • Structure (height, leaf area index, leaf size) • Physiology (photosynthetic capacity, stomatal conductance) • Soil • Roots • Microbes • Abiotic conditions (soil moisture, temperature, chemistry, texture) • Spatial-Temporal Variability • Spatial • Vertical (canopy) and Horizontal (footprint, landscape, functional type, disturbance) • Temporal • Dynamics • Diurnal • Seasonal • Inter-annual

  4. What a Tower Sees

  5. What the Atmosphere Sees Schulze, 2006 Biogeosciences

  6. Eddy Covariance

  7. Reality

  8. From the Field to your Dissertation

  9. Time Series Analysis: Raw Data

  10. Time Series: FingerPrint

  11. Time Series: Diurnal Pattern

  12. Time Series: Mean Diurnal Pattern

  13. Night time Biased Respiration

  14. CO2 Storage ‘Flux’

  15. Deciduous Broadleaved Forests

  16. Fourier Transforms

  17. Time Series: Spectral Analysis Baldocchi et al., 2001 AgForMet

  18. Stoy et al. 2005 Tree Physiol

  19. Time Series: Interannual Variability Data of Wofsy, Munger, Goulden, Harvard Univ

  20. Intern-annual Lag Effects Due to Drought/Heat Stress Knohl et al Max Planck, Jena

  21. Processes • Canopy Photosynthesis • Light • Temperature • Soil Moisture • Functional Type • Ecosystem Respiration • Temperature • Soil Moisture • Photosynthesis

  22. Concepts: NEE and Environmental Drivers From E. Falge

  23. Pulses, Switches and Lags are Important too! • They are Features of Complex Dynamical Systems • Biosphere is a Complex Dynamical System • Constituent Processes are Non-linear and Experience Non-Gaussian Forcing • Possess Scale-Emergent Properties • Experiences Variability Across a Spectrum of Time and Space Scales • Solutions are sensitive to initial conditions • Solutions are path dependent • Chaos or Self-Organization can Arise

  24. Light and Photosynthesis:Leaves, Canopies and Emerging Processes

  25. CO2 uptake-Light Response Curve: Crops Linear Function and High r2 (~0.90)

  26. CO2 uptake-Light Response Curve: Forest Function is Non-Linear and Low r2 (~0.50)

  27. CO2 flux vs Sunlight at different LAI Xu and Baldocchi, 2003, AgForMet

  28. Use Theory to Interpret Complex Field Data Patterns

  29. Ac vs Qp: Daily Sums Become Linear!? Leuning et al. 1995, PCE

  30. Role of Averaging Period: Hourly vs Daily Sims et al. AgForMet, 2005

  31. Role of Averaging Period: Snap Shot vs Daily Integral Sims et al 2005, AgForMet

  32. Canopy Light Response Curves: Effect of Diffuse Light

  33. CO2 Flux and Diffuse Radiation Niyogi et al., GRL 2004

  34. C Fluxes and Remote Sensing: NPP and NDVI of a Grassland Xu, Gilmanov, Baldocchi

  35. Rahman et al 2005 GRL

  36. Linking Water and Carbon: Potential to assess Gc with Remote Sensing Xu + DDB

  37. Land Surface Water Index (LSWI) plotted with daily NEE for 2004/2005 Land Surface Water Index LSWI = (ρ860 - ρ1640)/(ρ860 + ρ1640) PRI and NEE PRI = (r531 - r570) / (r531 + r570) Falk, Baldocchi, Ma

  38. Partitioning Carbon Fluxes

  39. Law and Ryan, 2005, Biogeochemistry

  40. De-Convolving Soil Respiration Kuzyakov, 2006

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