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FLUXNET after 10 Years: Synthesizing CO2 and Water Vapor Fluxes From Across a Global Network
Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley ILEAPS, Boulder, Jan 2006
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FLUXNET: From Sea to Shining Sea 379 Sites, circa 2006
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Global distribution of Flux Towers with Respect to Climate
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Evolution of FLUXNET Measure Annual Cycle of NEE
Micromet issues of Detrending, Transfer Functions, Flux Sampling and Measurements, Gap-filling, Error Assessment Measure and Interpret Intra-annual Variation of NEE Flux partitioning (GPP & Reco); assessment of metadata,e.g. Vcmax, soil respiration, LAI, biomass inventories. Measure and Interpret Inter-annual variations of NEE Measure NEE over multiple Land-Use Classes crops, grasslands, deciduous and evergreen broadleaf and conifer forests Disturbance, logging, biodiversity and fire Manipulative Studies Nitrogen and H2O additions Measure NEE over Representative Areas Scaling Flux Information of Footprint to MODIS pixel
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Successes Mountains of data from a spectrum of canopy roughness conditions, functional types and climate spaces have been collected A Model for Data Sharing FLUXNET Web Site, a venue for distributing Primary, Value-added and Meta-Data products Value-Added Products have been produced Development of Gap-Filling Techniques Production of Gap-Filled Daily and Annual Sums Data for Validating and Improving SVAT models used for weather, climate, biogeochemistry and ecosystem dynamics Collaboration & Synthesis through Workshops and Hosting Visitors Building a Collaborative, Cooperative, Multi-Disciplinary & International Community of Researchers Characterizing Annual C Fluxes Environmental Controls on NEE Training New and Next Generation of Scientists, Postdocs, Students
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‘Failures’/’Un-resolved’ Issues
Not Measuring Night-time Fluxes Well Not Measuring Fluxes over Complex terrain and during Advection Well ImPerfect U* correction New Gu Algorithm ImPerfect Flux Partitioning Works Better on Longer Time Scales ImPerfect Energy Balance Closure Could be ‘red-herring’ based on recent several talks at a SSSA workshop Need Better Outreach and Training
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Visions with a Flux Measurement Network
Processes Canopy-Scale Response Functions Emergent Processes Flux Partitioning, NEP=GPP-Reco Acclimation Time Daily/Seasonal Dynamics Pulses, Lags, Switches Intra- + Interannual Variability Stand Age/Disturbance Space Climate/Structure/Function Coherence/Gradients Upscaling with Remote Sensing New Directions
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Probability Statistics of NEE
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Light and Photosynthesis: Emergent Processes at Leaf and Canopy Scales
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Volcanoes, Aerosols + NEE
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CO2 Flux and Diffuse Radiation
Niyogi et al., GRL 2004
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Photosynthesis-Respiration
Processed by Falge
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NEE: Acclimation with Temperature
Analysis of E. Falge
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Respiration: Temperature and acclimation
Analyst: Enquist et al. 2003, Nature
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Linking Water and Carbon: Potential to assess Gc with Remote Sensing
Xu + DDB
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An Example of Scale Invariance
Processed by M. Falk
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Temporal Dynamics of C Fluxes
Hour Day Month Season Year Multiple Years Pulses Lags Switches
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Decadal Plus Time Series of NEE: Flux version of the Keeling’s Mauna Loa Graph
Data of Wofsy, Munger, Goulden et al.
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Complicating Dynamical Factors
Switches/Pulses Rain Phenology/Length of Season Frost/Freezing Emergent Processes Clouds & LUE Acclimation Lags Stand Age/Disturbance
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DRe vs DGPP
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Lag Effects Due to Drought/Heat Stress
Knohl et al Max Planck, Jena
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An Objective Indicator of Phenology??
Soil Temperature: An Objective Indicator of Phenology?? Data of Pilegaard et al.
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An Objective Measure of Phenology, part 2
Soil Temperature: An Objective Measure of Phenology, part 2 Data of: ddb, Wofsy, Pilegaard, Curtis, Black, Fuentes, Valentini, Knohl, Yamamoto. Granier, Schmid Baldocchi et al. Int J. Biomet, in press
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Spatial Gradients: NEE and Length of Growing Season
Coherent response among sites, impact of length of growing season. Does not account for interannual variability at a site, due to snow cover, drought, cloudy vs clear summers etc.
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Spatial Variations in C Fluxes
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Sims et al 2005 AgForMet
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Global MODIS Test Heinsch et al. in press
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Testbed for Ecohydrological Theory
Miller et al, Adv. Water Research, submitted
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Value of Flux Networks Produces Large and Long Data Sets
Reduced Sampling Error Robust Dataset for Model Development Study Spectra of Time Scales Capture Pulses and Lags Study Gradient of Climates, Structure and Function Field of Dreams: ‘Build it and they will Come’ Better Integrated Research Studies
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Future Directions Administrative Scientific
ReOrganize FLUXNET with Multiple/International Funding Sources Scientific NEE in Urban and Suburban, Africa, India, Latin America and High Arctic Environments Coupling CO2, Trace Gas Deposition/Emission (O3, voc) and Methane Fluxes Adopting New Technology (TDL, wireless networks) to embellish flux measurements Couple tower data with Real-time Data Assimilation Models. Boundary Layer Budgets using Fluxes and High Precision CO2 measurements Spectral reflectance measurements across the network Spatial-Temporal Network-Scale Analysis Real-time Data Assimilation Matching Footprints of Tower and Pixels Model Lags, Switches and Pulses Using Fluxnet data to assess problems in Ecology, Ecohydrology, Biogeochemistry, Biogeography, Remote Sensing, Global Modeling, Biodiversity
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Validating MODIS Falk, Ma, Baldocchi, unpublished
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Heinsch et al. submitted
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Tower vs Satellite NDVI
Falk et al., to be submitted
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Limits to Landscape Classification by Functional Type
Stand Age/Disturbance Biodiversity Fire Logging Insects/Pathogens Management/Plantations Kyoto Forests
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Effects of Stand Age: After Logging
Law et al Global Change Biology
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Biodiversity and Evaporation
Baldocchi, 2004: Data from Black, Schmid, Wofsy, Baldocchi, Fuentes
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