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AmeriFlux, Yesterday, Today and Tomorrow Dennis Baldocchi, UC Berkeley Margaret Torn and Deb Agarwal, Lawrence Berkeley National Lab Bev Law, Oregon State University Tom Boden, Oak Ridge National Laboratory

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AmeriFlux, circa 2012

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Growth in the Network Data from Bai Yang and Tom Boden

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Age of Flux Sites, and the Length of their Data Archive

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Pros and Cons of a Sparse Flux Network Pros Covers Most Climate and Ecological Spaces Long-Term Operation Experiences Extreme Events, Gradual Climate Change, and Disturbance Gradients of Sites across Landscapes and Regions Span Range of Environmental and Ecological Forcing Variables Clusters of Sites examine effects of Land Use Change, Management, and Disturbance (fire, drought, insects, logging, thinning, fertilizer, flooding, woody encroachment) Robust Statistics due to Over-Sampling Cons Cant Cover All Physical and Ecological Spaces or Complex Terrain Current Record is too Short to Detect Climate or CO2-Induced Trends Flux Depends on Vegetation in the Footprint Bias Errors at Night, Under Low Winds

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The Type of Network Affects the Type of Science Sparse Network of Intense Super-Sites and Clusters of Sites, Producing Mechanistic Information can Test, Validate and Parameterize Process and Mechanistic Models Denser and More Extensive Network of Less- Expensive Sites can Assist in Statistical and Spatial Up-Scaling of Fluxes with Remote Sensing

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Climate Space of AmeriFlux Sites Yang et al 2008, JGR Biogeosciences

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AmeriFlux Sites, Circa 2003, and Ecosystem/Climate Representativeness Hargrove, Hoffman and Law, 2003 Eos

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Representativeness of AmeriFlux, Circa 2008 (blue is good!) Yang et al. 2008 JGR Biogeosciences

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Basis of a Successful Flux Network It Takes People (Scientists, Postdocs, Students and Technicians) Social Network that Facilitates Meetings, Workshops, Shared Leadership and a Shared/Central Data Base This Fosters Getting to Know Each Other, Collaboration, Communication, Common Vision, Shared Goals, And Joint Authorship of Synthesis Papers

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Past and Current Leadership Dave Hollinger, Chair 1997-2001 Bev Law, Chair 2001-2011 Margaret Torn AmeriFlux PI, 2012- Tom Boden AmeriFlux Data Archive

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Published Use of AmeriFlux Data 184 Papers linked to key word AmeriFlux These Papers have been cited over 7000 Times 246 Papers linked to key word Fluxnet

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Issues of standardization, or not?

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Know Thy Site Ray Leuning Most Flux Instruments are Very Good; Pick the Instrument System that is Most Appropriate to Your Weather and Climate

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Open-Path CO 2 Fluxes were 1.7% Higher than Closed Path Fluxes Schmidt et al. 2012, JGR Biogeosciences

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Site Calibration with Roving Standard Schmidt et al 2012 JGR Biogeosciences

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Extrinsic Contributions Data Contribute to Producing Better Models via Validation, Parameterization, Data-Assimilation & Defining Functional Responses Land-Vegetation-Atmosphere-Climate Energy Partitioning, Albedo, Energy Forcing, Land Use Remote Sensing, Light Use Efficiency Models Regional and Global GPP models Ecosystem and Biogeochemical Cycling Carbon Cycle, Disturbance, Phenology, Environmental Change, Plant Functional Types Hydrology Evaporation, Soil Moisture, Ground-Water, Drought

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Lessons Learned

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Whats in the Data? Magnitudes and Trends in Annual C and H2O Fluxes, by Plant Functional Type and Climate Space Light-Use, Temperature, Rain Response Functions Emergent-Scale Properties Diffuse Light Rain Pulses Drought and Ground Water Access Disturbance Insect Defoliation Fire, Logging and Thinning Drought and Mortality BioPhysical Forcings Albedo and Temperature Energy Partitioning with Land Use

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C Fluxes are a Function of Time Since Disturbances, as well as Weather, Structure and Function Urbanski et al. 2007 JGR Biogeosciences

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Gilmanov et al 2010 Range Ecology & Management Light Response Curves of CO 2 Flux are Quasi-Linear, Deviating from Monteiths Classic Paper and Impacting the Interpretation of C Flux with Remote Sensing

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Niyogi et al 2004 GRL Light Use Efficiency INCREASES with the Fraction of Diffuse Light

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Response Functions from Elevation/Climate Gradients Anderson-Teixeira et al. 2010 GCB

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Respiration is a function of Temperature, Soil Moisture, Growth, Rain Pulses And Temperature Acclimation Xu et al. 2004 Global Biogeochemical Cycles

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Rain-Induced Pulses in Respiration: Long Term Studies Capture More Pulses, Better Statistics Ma et al. 2012 AgForMet

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Disturbance, Fire and Thinning Dore et al. 2012 GCB

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Insect Defoliation, 2007 Clark et al. 2010 GCB

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Disturbance Dynamics C Flux = f(time since disturbance) Amiro et al. 2010 JGR Biogeosci

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Flux Phenology Gonsamo et al 2012 JGR Biogeosci

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Satellite vs Flux Phenology Gonsamo et al 2012 JGR Biogeosci

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Its Not only CO2! Effects of Precipitation and Energy on Evaporation Williams et al. 2012 WRR MI Budyko

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Schwalm et al 2012 Nature Geoscience Long-Term Studies can Assess Links between Drought and Fluxes

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Schwalm et al 2012 Nature Geoscience Net Negative Effects on Carbon and Water Fluxes are Strong: What about 2012?

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Lee et al Nature 2011 Land Use and Climate Forests are warmer than nearby Grasslands

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Light Use Efficiency Models: Upscale Fluxes from Towers to Regions Yuan et al. 2007, AgForMetHeinsch et al 2006 IEEE

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Sims et al 2005 AgForMet C and Water fluxes Derived from Satellite-Snap Shots Scale with Daily Integrated Fluxes from Eddy Covariance Ryu et al. 2011 AgForMet

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Seasonal Maps of NEE, via Regression Tree Analysis, on AmeriFlux and Modis Data Xiao et al. 2008 AgForMet

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Chen et al 2011 Biogeosciences What is the Truth?; How Good is Good-Enough?

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Regional Estimates of Fire, Drought, Hurricanes on NEE Xiao et al. 2011 AgForMet

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Krinner et al 2005 GBC Using Flux Data to Validate Dynamic Vegetation Models-ORCHIDEE

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Data-Model Fusion/Assimilation Sacks et al. 2006 GCB

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Model Hierarchy Testing: How Much Detail is Needed? Bonan et al 2012 JGR Biogeosci

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Richardson et al, 2012 GCB Testing Phenology Predictions in Ecosystem-Dynamic Models The total bias in modeled annual GEP was +35 365 g C m-2 yr-1 for deciduous forests +70 335 g C m-2 yr-1 for evergreen forests across all sites, models, and years;

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Its Not Just About CO 2 : Significant change in albedo with 3 disturbance types OHalloran et al 2012 GCB Albedo change produces radiative forcing of same magnitude as CO 2 forcing in case studies of forest mortality from hurricane defoliation, pine beetles, and fire. Beetle effect occurs mostly after snags fall HurricaneFireBeetles

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Hollinger et al 2009 Global Change Biology Albedo Scales with Nitrogen We can Use Albedo to Parameterize N and Ps Capacity in Models!

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The Albedo-N Correlation may be Spurious Knyazikhin et al 2012 PNAS report that the previously reported correlation is an artifactit is a consequence of variations in canopy structure, rather than of %N. When the BRF data are corrected for canopy-structure effects, the residual reflectance variations are negatively related to %N at all wavelengths in the interval 423855 nm. To infer leaf biochemical constituents, e.g., N content, from remotely sensed data, BRF spectra in the interval 710790 nm provide critical information for correction of structural influences an increase in the amount of absorbing foliar constituents enhances absorption and correspondingly decreases canopy reflectance

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Validating and Improving Climate Drivers, like Net Radiation Fields Jin et al 2011 RSE

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Radiation and Evaporation Maps

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Miller et al 2007 Adv Water Res Testing Ecohydrology Theories for Soil Moisture

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Current and Future Collaborations COSMOS and Soil Moisture Fields Validation of Satellite based estimates of CO2, LIDAR, Albedo, and Soil Moisture (SMOS, SMAP, AIRMOSS) Priors for CO2-Satellite Inversions (GOSAT, OCO) Data-Model Assimilation Phenology and Pheno-Camera Networks FLUXNET and NEON

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Simard et al 2011 JGR Biogeosciences Importance of Site Metadata, A Plea for more LIDAR data to Test New Satellite Products and Force 3D Ecosystem Dynamic Models Medvigy et al 2009 JGR Biogeoscience

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AmeriFlux Plans DOE grant to LBL to Manage 10-12 Long Term Clusters of Flux Towers Ensure Cohort of Long Term Sites Extend into the Future to Address Ecological and Climate Questions on their Native Time Scales Continue Operation of Roving Calibration system to All AmeriFlux Sites Central Data Archiving, Processing and Data Distribution Open Access, Prompt Submission, Uniform Processing Spare Sensors for Emergencies

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Registered AmeriFlux Sites