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Tracking the emission and transport of pollution from wildfires using the IASI CO retrievals: analysis of the summer 2007 Greek fires

In this paper, we analyze the performance of the Infrared Atmospheric Sounding Interferometer (IASI), launched in October 2006 on board METOP-A, for the monitoring of carbon monoxide (CO) during extreme fire events, focusing on the record-breaking fires which devastated thousands of square kilometer...

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Bibliographic Details
Published in:Atmospheric chemistry and physics discussions 2009-03, Vol.9 (2), p.7413-7455
Main Authors: Turquety, S, Hurtmans, D, Hadji-Lazaro, J, Coheur, P-F, Clerbaux, C, Josset, D, Tsamalis, C
Format: Article
Language:English
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Summary:In this paper, we analyze the performance of the Infrared Atmospheric Sounding Interferometer (IASI), launched in October 2006 on board METOP-A, for the monitoring of carbon monoxide (CO) during extreme fire events, focusing on the record-breaking fires which devastated thousands of square kilometers of forest in Greece during the last week (23-30) of August 2007. After an assessment of the quality of the profiles retrieved using the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, the information provided on fire emissions and subsequent pollution outflow is discussed. Large CO plumes were observed above the Mediterranean Basin and North Africa, with total CO columns exceeding 3010 super(18) molecules/cm super(2) and absolute volume mixing ratio up to 22 ppmv. The average root-mean-square (RMS) difference between simulated and observed spectra is close to the estimated radiometric noise level, slightly increasing (by ~14%) in the fresh fire plumes. CO profiles are retrieved with a vertical resolution of about 8 km, with ~1.7 pieces of independent information on the vertical in the region considered and a maximum sensitivity in the free troposphere (~4-5 km). Using the integrated total amount, the increase in CO burden due to these fires is estimated to 0.321 Tg, ~40% of the total annual anthropogenic emissions in Greece. These CO enhancements are in good agreement with the aerosol optical depth (AOD) retrieved from the MODIS measurements, highlighting a rapid transport of trace gases and aerosols across the Mediterranean Basin (less than one day). While the coarse vertical resolution will not allow the location of the exact plume height, the large CO enhancements observed in the lower troposphere are consistent with the maximum aerosol backscatter coefficient at ~2 km detected by the CALIPSO lidar in space (CALIOP). This indicates that the general level of transport can be derived (lower, middle or upper troposphere) but that it needs to be accompanied by a systematic confrontation with sensitivity profiles and boundary layer height.
ISSN:1680-7367
1680-7375