Data Assimilation for AmeriFlux: Toward Transforming . . .

Data Assimilation for AmeriFlux: Toward Transforming the AmeriFlux Network into an Observing System on Continental Scale CarbonCycle DynamicsThe objectives are: (1) to use data assimilation approaches tailored to the characteristics of individual fluxsites to generate AmeriFlux network-wide flux reanalysis products that are biophysically and biogeochemically consistent andtemporally complete and to partition net ecosystem exchanges into component contributions; (2) to synthesize the spatial andtemporal variations of critical ecosystem parameters estimated through data assimilation and needed by prognostic carbon cyclemodels and remote sensing-based primary production models for simulating large scale terrestrial carbon fluxes. We will apply theAmeriFlux Data Assimilation System which can assimilate diverse flux and other complementary measurements from eddy flux sitesthrough a variational method into a comprehensive, mechanistic ecosystem model that couples the exchanges of CO2, water vapor, andenergy.The reanalysis products from this proposed research will greatly improve AmeriFlux network-wide synthesis capabilitiesand help transform AmeriFlux into an integrated carbon cycle observing system and thus fulfill an expectation of the North AmericanCarbon Program on AmeriFlux. The synthesis of fundamental ecosystem parameters will help remove a bottleneck that limits large-scaleapplications of prognostic terrestrial carbon cycle models and remote sensing-based models. We will integrate AmeriFlux dataassimilation with the National Terrestrial Carbon Model.