Kustas, William (USDA-ARS, Beltsville, MDUSDA-ARS HRSL, Bldg. 007, BARC-WEST, Beltsville, MD, 20705; Phone: 301-504-8498; Fax: 301-504-8931; Email: bkustas@hydrolab.arsusda.gov)

Monitoring Net Carbon Exchange over Agricultural Landscapes with a Remote Sensing-Based Model

M.C.Anderson, W.P.Kustas *, J.M.Norman

New generation carbon-flux-monitoring campaigns are recognizing the need to establish connectivity between intensive surface observations, typically collected at a point or a distributed set of points, by placing them within a regional context using modeling supported by remote sensing. Large-scale carbon flux networks, such as AmeriFlux and EuroFlux, will require robust methodologies for upscaling and integrating observations made at individual towers to be able to draw regional inferences regarding terrestrial carbon cycles. An existing nested remote sensing scheme, designed for mapping surface water and energy flux distributions at spatial resolutions from 10 m to 5 km, has recently been modified to incorporate an analytical light-use efficiency (LUE) submodule for modeling bulk canopy conductance and carbon uptake. This analytical LUE technique was distilled out of a more detailed soil-plant-atmosphere model for purposes of practical application, and has been demonstrated to provide good predictions of coupled transpiration and carbon assimilation fluxes using only a modest amount of input data. This modeling system is applied to remote sensing imagery over Oklahoma and the output is compared to carbon flux measurements collected during the intensive field experiment. Results illustrate the utility of the technique for large scale monitoring of net carbon exchange for agricultural landscapes.