Constraining CO Emissions Using MOPITT, TES, and OMI Satellite Retrievals
Monday, 15 December 2014: 9:45 AM
Atmospheric carbon monoxide (CO) is a product of incomplete combustion and oxidation of hydrocarbons. To model global CO concentrations accurately, a good representation of surface sources is critical. In recent years, several studies have tried to estimate CO sources using a top-down approach. It was found that model errors have a detrimental impact on the quality of the estimated emissions. Using the GEOS-Chem 4D-Var chemical data assimilation system, we try to mitigate the impact of errors in the model chemistry by constraining the distribution of the hyrdoxyl radical (OH), the principal sink of CO in the atmosphere. Since OH is influenced by the abundances of ozone (O3) and nitrogen oxides (NOx), we assimilate satellite retrievals of O3 from the Tropospheric Emission Spectrometer (TES) and of nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) alongside retrievals of CO from the Measurement of Pollution in the Troposphere (MOPITT). We examine the impact of assimilating these observations on the modeled OH abundances, as well as on the estimated emissions of CO and NOx.