Carbon Flux Quantification in the Great Plains

This paper (submitted) presents the methodology and results of two ecological-based net ecosystem production (NEP) regression tree models capable of up scaling measurements made at various flux tower sites throughout the U.S. Great Plains. Separate grassland and cropland NEP regression tree models were trained using various remote sensing data and other biogeophysical data, along with 15 flux towers contributing to the grassland model and 15 towers for the cropland model. The models yielded weekly average daily grassland and cropland NEP maps of the U.S. Great Plains at 250 meter resolution for 2000 2008. The grassland and cropland NEP maps were spatially summarized and statistically compared. The results of this study indicate that grassland and cropland ecosystems generally perform as weak net carbon (C) sinks, absorbing more C from the atmosphere than they release. A closer look into the weekly time series reveals the C fluctuation through time and space for each land cover type.