Evaluating atmospheric CO2 inversions at multiple scales over a highly inventoried agricultural landscape |
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| Authors: | Andrew E Schuh Thomas Lauvaux Tristram O West A Scott Denning Kenneth J Davis Natasha Miles Scott Richardson Marek Uliasz Erandathie Lokupitiya Daniel Cooley Arlyn Andrews Stephen Ogle |
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| Institution: | 1. Cooperative Institute for Research in the Atmosphere, Colorado State University, , Fort Collins, CO, USA;2. Natural Resources Ecology Laboratory, Colorado State University, , Fort Collins, CO, USA;3. Department of Meteorology, Pennsylvania State University, , University Park, PA, USA;4. Joint Global Change Research Institute, Pacific Northwest National Laboratory, , College Park, MD, USA;5. Department of Atmospheric Sciences, Colorado State University, , Fort Collins, CO, USA;6. Department of Zoology, University of Colombo, , Colombo 03, Sri Lanka;7. Department of Statistics, Colorado State University, , Fort Collins, CO, USA;8. NOAA Earth System Research Laboratory, , Boulder, CO, USA |
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| Abstract: | An intensive regional research campaign was conducted by the North American Carbon Program (NACP) in 2007 to study the carbon cycle of the highly productive agricultural regions of the Midwestern United States. Forty‐five different associated projects were conducted across five US agencies over the course of nearly a decade involving hundreds of researchers. One of the primary objectives of the intensive campaign was to investigate the ability of atmospheric inversion techniques to use highly calibrated CO2 mixing ratio data to estimate CO2 flux over the major croplands of the United States by comparing the results to an inventory of CO2 fluxes. Statistics from densely monitored crop production, consisting primarily of corn and soybeans, provided the backbone of a well studied bottom‐up inventory flux estimate that was used to evaluate the atmospheric inversion results. Estimates were compared to the inventory from three different inversion systems, representing spatial scales varying from high resolution mesoscale (PSU), to continental (CSU) and global (CarbonTracker), coupled to different transport models and optimization techniques. The inversion‐based mean CO2‐C sink estimates were generally slightly larger, 8–20% for PSU, 10–20% for CSU, and 21% for CarbonTracker, but statistically indistinguishable, from the inventory estimate of 135 TgC. While the comparisons show that the MCI region‐wide C sink is robust across inversion system and spatial scale, only the continental and mesoscale inversions were able to reproduce the spatial patterns within the region. In general, the results demonstrate that inversions can recover CO2 fluxes at sub‐regional scales with a relatively high density of CO2 observations and adequate information on atmospheric transport in the region. |
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| Keywords: | agriculture atmospheric inversions carbon cycle CO2 emissions inventory Mid‐Continent Intensive |
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