Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere

1. Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley AsiaFlux, Seoul, Korea Nov. 17, 2008

2. Contemporary CO2 Record

3. Methods To Assess Terrestrial Carbon Fluxes at Landscape to Continental Scales, and Across Multiple Time Scales GCM Inversion Modeling Eddy Flux Measurements/ FLUXNET Remote Sensing/ MODIS Forest/Biomass Inventories Physiological Measurements/ Manipulation Expts. Biogeochemical/ Ecosystem Dynamics Modeling

4. Objectives • Time • Annual Integration • Seasonal Dynamics • Inter-Annual Variability • Disturbance/Chronosequence • Processes • Photosynthesis = f(Q,T,functional type) • Respiration = f(T, growth, ppt, q) • Space • Other Uses and Application • Ecosystem Modeling

5. Temporal Dynamics of C Fluxes • Hour • Day • Month • Season • Year • Multiple Years • Pulses • Lags • Switches

6. Probability Distribution of Published NEE Measurements, Integrated Annually Baldocchi, Austral J Botany, 2008

7. Does Net Ecosystem Carbon Exchange Scale with Photosynthesis? Ecosystems with greatest GPP don’t necessarily experience greatest NEE Baldocchi, Austral J Botany, 2008

8. Ecosystem Respiration Scales Tightly with Ecosystem Photosynthesis, But Is with Offset by Disturbance Baldocchi, Austral J Botany, 2008

9. Net Ecosystem Carbon Exchange Scales with Length of Growing Season Baldocchi, Austral J Botany, 2008

10. Decadal Plus Time Series of NEE:Flux version of the Keeling’s Mauna Loa Graph Data of Wofsy, Munger, Goulden, et al.

11. Interannual Variation and Long Term Trends in Net Ecosystem Carbon Exchange (FN), Photosynthesis (FA) and Respiration (FR) Urbanski et al 2007 JGR

12. Lag Effects Due to 2003 European Drought/Heat Stress Knohl et al Max Planck, Jena

13. Interannual Variations in Photosynthesis and Respiration are Coupled Baldocchi, Austral J Botany, 2008

14. Interannual Variability in NEE is tiny across the Global Network

15. Interannual Variability in GPP is tiny across the Global Network, too

16. Little Change in Abiotic Drivers--annual Rg, ppt --across Network

17. Complicating Dynamical Factors • Switches • Phenology • Drought • Frost/Freeze • Pulses • Rain • Litterfall • Emergent Processes • Diffuse Light/LUE • Acclimation • Lags • Stand Age/Disturbance

18. Soil Respiration Lags Photosynthesis onHourly Scale Tang et al. 2006, GCB

19. Emergent Scale Process:CO2 Flux and Diffuse Radiation • We are poised to see effects of Cleaner/Dirtier Skies and Next Volcano Niyogi et al., GRL 2004

20. Potential and Real Rates of Gross Carbon Uptake by Vegetation: Most Locations Never Reach Upper Potential GPP at 2% efficiency and 365 day Growing Season tropics GPP at 2% efficiency and 182.5 day Growing Season FLUXNET 2007 Database

21. Optimal NEE: Acclimation with Temperature E. Falge et al 2002 AgForMet; Baldocchi et al 2001 BAMS

22. Soil Temperature: An Objective Indicator of Phenology?? Data of Pilegaard et al.

23. Soil Temperature: An Objective Measure of Phenology, part 2 Baldocchi et al. Int J. Biomet, 2005

24. Do Snap-Shot C Fluxes, inferred from Remote Sensing, Relate to Daily C Flux Integrals? Sims et al 2005 AgForMet

25. Spatial Variations in C Fluxes Xiao et al. 2008, AgForMet

26. Upscaling Flux Data with Remote Sensing Data Published, Global: -182 gC m-2 y-1 Map, US: -189 gC m-2 y-1 Xiao and Baldocchi, unpublished

27. Spatialize Phenology with Transformation Using Climate Map Baldocchi, White, Schwartz, unpublished

28. Flux Based Phenology Patterns with Match well with data from Phenology Network White, Baldocchi and Schwartz, unpublished

29. Limits to Landscape Classification by Functional Type • Stand Age/Disturbance • Biodiversity • Fire • Logging • Insects/Pathogens • Management/Plantations • Kyoto Forests

30. Time Since Disturbance Affects Net Ecosystem Carbon Exchange Baldocchi, Austral J Botany, 2008 Data of teams lead by Amiro, Dunn, Paw U, Goulden

31. Other Activities and Uses of Fluxnet Data • Landuse • Ecosystem Modeling • EcoHydrology • Biodiversity • Climate

32. Biodiversity and Evaporation Baldocchi, 2004: Data from Black, Schmid, Wofsy, Baldocchi, Fuentes

33. Ecosystem Model Testing and Development Kucharik et al., 2006 Ecol Modeling

34. Seasonality of Photosynthetic Capacity Wang et al, 2007 GCB

35. Optimizing Seasonality of Vcmax improves Prediction of Fluxes Wang et al, 2007 GCB

36. A Continuing Challenge and Task: Measure Ecosystem Processes on Ecosystem Timescales ‘A continuing challenge to long-term Earth observations is the prejudice against science that is not directly aimed at hypothesis testing. At a time when the planet is being propelled by human action into another climate regime with incalculable social and environmental costs, we cannot afford such a rigid view of the scientific enterprise. The only way to figure out what is happening to our planet is to measure it, and this means tracking changes decade after decade and poring over the records. A point of diminishing scientific returns has never been realized in what is now known as the "Keeling Curve," the Mauna Loa CO2 record’. Ralph Keeling, Science March 28, 2008

37. Acknowledgements • Leadership • Riccardo Valentini, Steve Running, Bev Law • Data Preparation: FLUXNET-2007 • Dario Papale, Markus Reichstein, Catharine Van Ingen, Deb Agarwal, Tom Boden, Bob Cook, Susan Holliday, Bruce Wilson, +++ • FLUXNET Office @ Berkeley • Eva Falge, LianhongGu, Matthias Falk, Rodrigo Vargas, Youngryel Ryu • Networks • AmeriFlux, CarboEurope, AsiaFlux, ChinaFlux, Fluxnet Canada, OzFlux, +++ • Agencies • NSF/RCN, ILEAPS, DOE/TCP, NASA, Microsoft, ++++