Aerosol Direct Radiative Effect over clouds from SCIAMACHY
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Aerosol Direct Radiative Effect over clouds from SCIAMACHY |
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SCIAMACHY aerosol DRE data over clouds explanation |
The Aerosol Direct Radiative Effect (DRE) over clouds was computed using SCIAMACHY reflectances for all cloud scenes in an area over the south-east Atlantic (20°W - 10°E, 20°S - 10°N) from 2006 to 2009, during the months June - September. This is a period of massive vegetation burning in southern Africa during the dry season and often smoke plumes can be observed drifting over the Atlantic ocean. The aerosol DRE from SCIAMACHY indicates the warming effect of the smoke when it overlies clouds due to absorption of sunlight. This is measured in Watts per square meter (Wm-2). The images show an overview of the warming effect on a particular day. The SCIAMACHY aerosol DRE is overplotted over MODIS RGB showing clouds. However, the MODIS instrument passes over this area in the afternoon (around 13.00-14.00 UTC), while SCIAMACHY passes over in the morning (around 10.30 UTC), so the image and the data were acquired about 3.5 hours apart. MODIS was used, to compare the data more easily to the OMI data here. The exact times are indicated in the image. An example of SCIAMACHY DRE over clouds acquired by MERIS (which was on EnviSat together with SCIAMACHY, and thus viewed the area at the same time) can be seen here Below the main features in the aerosol DRE over clouds images are explained.
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