Regional and Global Estimation of Terrestrial CO2 Exchange from NIGEC Flux Data

of Proposed Work: We will perform a scaling analysis of terrestrial carbon exchange using several of the NIGEC flux sites in different biomes (forest, C 4 grassland, C 3 agriculture), using a numerical model of the biophysics and biogeochemistry of plants and soils (SiB2), which includes calculations of the surface fluxes of CO 2 , energy, and moisture. This model will be used to analyze local fluxes at each site based on observed meteorology and soil conditions, and then the site-calibrated model will be coupled to a series of atmospheric models on increasing spatial scales and with decreasing reliance on a knowledge of local conditions. These atmospheric models will include a 1-dimensional model of PBL turbulence with a grid spacing of about 10 m, a 3-D mesoscale model (RAMS) with a grid spacing of about 6 km, and a global atmospheric general circulation model (CSU GCM), with a grid spacing of about 400 km. This spectrum of atmospheric calculations will provide insight into the coupling between atmospheric transport and terrestrial ecosystem metabolism over a range of spatial scales. Our results will allow the tower flux measurements to be generalized in both space and time, providing a means for NIGEC to leverage its investment in the data collection and to obtain regional and global estimates of sources and sinks of CO 2 , and will be useful in understanding the processes controlling land surface climate and CO 2 flux.