Fluxnet 2009 Progress Dennis Baldocchi, Rodrigo Vargas, Youngryel Ryu, Markus Reichstein, Dario Papale, Deb Agarwal, Catharine Van Ingen AmeriFlux 2009

FLUXNET: From Sea to Shining Sea 500+ Sites, circa 2009

Global distribution of Flux Towers Covers Climate Space Well Can we Integrate Fluxes across Climate Space, Rather than Cartesian Space?

FLUXNET Community Outreach NewsLetter, FluxLetter Asilomar Workshop Distributed Searchable Database, Fluxnet Visitors – Paul Stoy, Sebastiaan Luysaaert, Josep Penuelas, Bart Kruijt

Fluxnet Modeling and Data Workshop Asilomar Conference Questions/Topics: What is the FLUXNET Measurement Community providing to the Modeling Community? What information and data products do modelers need from the FLUXNET measurement community? How can sensitivity runs from land surface models help us interpret flux data across climate gradients and plant functional types? Future composition of FLUXNET

Data Archive, Synthesis, Searchable and Manipulative Database

Progress on the ‘LaThuile’ Synthesis Papers

Water Use Efficiency, Coupling Water and Carbon Fluxes Beer et al Global Biogeochemical Cycles

Scales of Flux Variance Paul Stoy et al, Biogeosciences, Submitted

Vargas et al. New Phytologist, in press Role of Mycorrhyzae and C Fluxes

Results and Discussion

Emerging Ideas, Science Beyond Routine Flux Measurements Continental/Global Upscaling in Time/Space Flux Spectra across scales of Hours to Decade PhotoDegradation Site MetaData Syntheses – Leaf clumping, albedo Model Data Assimilation

Towards Continental and Global Representativeness The Network is not like Acupuncture (credit M Reichstein). Fluxes from Towers represent far beyond their geographical domain. But we are not Everywhere, All the Time, so We must rely on partnerships with Remote Sensing and Meteorological Data to Upscale

Spatial Variations in C Fluxes Xiao et al. 2008, AgForMet spring summer autumn winter

Using Flux Data to produce Global ET maps, V1 ET (mm H 2 O y -1 ) Fig.9 Global Evapotranspiration (ET) driven by interpolated MERRA meteorological data and 0.5º×0.6º MODIS data averaged from 2000 to Wenping Yuan

Martin Jung Using Flux data to produce Global ET maps, v2

How many Towers are needed to estimate mean NEE, And assess Interannual Variability, at the Global Scale? We Need about 75 towers to produce robust Statistics

How Big Does the Network Need to Be?

Over-Arching Questions relating to Statistical Representativeness As the sparse Network has grown, can it provide a Statistically- Representative sample of NEE, GPP and Reco to infer Global Behavior?, e.g. Polls sample only a small fraction of the population to generate political opinion Can Processes derived from a Sparse-Network be Upscaled with Remote Sensing and Climate Maps?; e.g. We don’t need to be everywhere all the time; We can use Bayes Theorem and climate records to upscale. If mean Solar inputs and Climate conditions are invariant, on an annual and a global-basis,are NEE, GPP and Reco constant, too?; e.g. global GPP scales with solar radiation which is constant

Apply Bayes Theorem to FLUXNET? Estimate Global flux by Integrating p(Flux|climate) across Globally-gridded Climate space p(flux) from FLUXNET p(climate|flux) prior from FLUXNET p(climate) from climate database

Probability Distribution of Published NEE Measurements, Integrated Annually

Global GPP = 1033 * m 2 = PgC/y Probability Distribution of Published GPP Measurements, Integrated Annually

Joint pdf GPP, Solar Radiation and Temperature E[GPP]= 1237 gC m -2 y -1 ~136 PgC/y

What Happens to the Grass? October June

Vaira Ranch, 2007

PhotoDegradation Baldocchi, Ma, Rutledge

Remote Sensing of Canopy Structure and GPP

Remote Sensing and Ecosystem Metabolism

VI vs GPP when including all data. LED spectral region (white box) looks showing good correlation, but the high correlation region is large. White rectangle box indicates LED spectral region

Williams et al Biogeosciences Incorporating Soil Evaporation Scheme in CABLE Improves Model Performance

Vargas et al New Phytologist, in press

Priestley-Taylor and Surface Conductance Chris Williams

Testing Budyko Chris Williams: EcoHydrology

Beer et al Global Biogeochemical Cycles And, WUE scales with LAI and Soil Moisture

Apparent clumping index can constrain true clumping index Ryu, Nilson, Kobayashi, Sonnentag, Baldocchi (to be submitted)

Hollinger et al 2009 Global Change Biology Albedo and Nutrition

Heat absorbedHeat reflected Croplands Deciduous Evergreen Grasslands Savannas Integrated annual error, or departure in the shortwave energy budget, for each site as derived from the calculated biome mean albedo. Albedo and Climate Forcing Tom O’Hallaran

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