The zonal structure of tropical O<sub>3</sub> and CO as observed by the Tropospheric Emission Spectrometer in November 2004 – Part 1: Inverse modeling of CO emissions
- ISSN: 1680-7324
- DOI: 10.5194/acp-9-3547-2009
We conduct an inverse modeling analysis of measurements of atmospheric\nCO from the TES and MOPITT satellite instruments using the GEOS-Chem\nglobal chemical transport model to quantify emissions of CO in the\ntropics in November 2004. We also assess the consistency of the\ninformation provided by TES and MOPITT on surface emissions of CO. We\nfocus on the tropics in November 2004, during the biomass burning\nseason., because TES observations of CO and O-3 and MOPITT observations\nof CO reveal significantly greater abundances of these gases than\nsimulated by the GEOS-Chem model during that period. We find that both\ndatasets suggest substantially greater emissions of CO from\nsub-equatorial Africa and the Indonesian/Australian re-ion than in the\nclimatological emissions in the model. The a posteriori emissions from\nsub-equatorial Africa based on TES and MOPITT data were 173 Tg CO/yr and\n184 Tg CO/yr, respectively, compared to the a priori of 95 Tg CO/yr. In\nthe Indonesian/Australian region, the a posteriori emissions inferred\nfrom TES and MOPITT data were 155 Tg CO/yr and 185 Tg CO/yr,\nrespectively, whereas the a priori was 69 Tg CO/yr. The differences\nbetween the a posteriori emission estimates obtained from the two\ndatasets are generally less than 20%. The a posteriori emissions\nsignificantly improve the simulated distribution of CO, however, large\nregional residuals remain, and are likely due to systematic errors in\nthe analysis. Reducing these residuals and improving the accuracy of\ntop-down emission estimates will require better characterization of\nsystematic errors in the observations and the model (chemistry and\ntransport).