10 Years of CO Flux Inversion with Assimilation of MOPITT and IASI Observations - Focus on Forest Fires over Southern and Northern America
Abstract
Carbon monoxide (CO) is an air pollutant and a key player in atmospheric chemistry. Accurate representations of the location and magnitude of CO surface emissions are required to accurately quantify the global CO flux signal. The magnitude of CO emissions from different sources categories is not well quantified. Emissions from biomass burning (BB) bring large uncertainties due to the variability of fires in both space and time. Satellites measuring CO by infrared (IR) remote sensing allow to improve our ability to map CO and to understand its variability. Among these orbiting instruments, there are the Measurements of Pollution in the Troposphere (MOPITT) from satellite TERRA and the Infrared Atmospheric Sounding Interferometer (IASI) on board satellite Metop-A.
The goal of this study is to setup a framework of CO emissions from MOPITT and IASI data for the 2008-2016 period with a focus on BB from boreal forests in Canada and tropical forests in Southern America. CO column retrievals from MOPITT v7 and IASI-FORLI are assimilated jointly. We apply a 4D-VAR data assimilation system to optimize CO emissions and to reduce the uncertainty of emission estimates from individual sources using the global chemistry transport model TM5. The 6°x4° global version of TM5 with 25 vertical levels has been used. Thanks to a high spatio-temporal coverage, IASI is a sensitive sensor to CO emissions as good as MOPITT which has a higher sensitivity in the lower troposphere than IASI. As previous studies have shown, information of CO sensors measuring the thermal IR come from the mid-troposphere. Combination of IASI and MOPITT assimilated in TM5 allows hence an accurate vertical structure in the troposphere and a better exploitation of CO emissions. According to previous studies, fires from boreal forests have higher level of smoldering than tropical forests. The assimilation of IASI and MOPITT improves CO estimations and allows to accurately observe differences of CO magnitudes between both forest fires. Validation against the Total Carbon Column Observing Network (TCCON) shows good agreement of CO flux magnitude and variability. CO plumes resulting from BB are also discussed. The future objective will be to combine CO and CO2 data from MOPITT and IASI in order to observe the link of these two gases with a higher resolution in the troposphere.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A51R2508P
- Keywords:
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- 0322 Constituent sources and sinks;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0325 Evolution of the atmosphere;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 0480 Remote sensing;
- BIOGEOSCIENCES