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

Contemporary CO 2 Record

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

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

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

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

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

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

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

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

Interannual Variation and Long Term Trends in Net Ecosystem Carbon Exchange (F N ), Photosynthesis (F A ) and Respiration (F R ) Urbanski et al 2007 JGR

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

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

Interannual Variability in NEE is tiny across the Global Network

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

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

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

Soil Respiration Lags Photosynthesis on Hourly Scale Tang et al. 2006, GCB

Emergent Scale Process: CO 2 Flux and Diffuse Radiation Niyogi et al., GRL 2004 We are poised to see effects of Cleaner/Dirtier Skies and Next Volcano

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Seasonality of Photosynthetic Capacity Wang et al, 2007 GCB

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

‘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 CO 2 record’. Ralph Keeling, Science March 28, 2008 A Continuing Challenge and Task: Measure Ecosystem Processes on Ecosystem Timescales

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 Berkeley –Eva Falge, Lianhong Gu, Matthias Falk, Rodrigo Vargas, Youngryel Ryu Networks –AmeriFlux, CarboEurope, AsiaFlux, ChinaFlux, Fluxnet Canada, OzFlux, +++ Agencies –NSF/RCN, ILEAPS, DOE/TCP, NASA, Microsoft, ++++