Wednesday, 14 January 2009: 8:30 AM
Direct aerosol radiative effect estimated with OMI, MISR and CERES observations over northern Africa
Room 131B (Phoenix Convention Center)
We examine aerosol optical thickness (AOT) products from Terra-MISR, Deep Blue Aqua-MODIS and Aqua-OMI over North Africa from June to September, 2005 and 2006. Daily AOT is estimated using linear regression relationships between daily MISR AOT and OMI UV Aerosol Index. This estimated AOT compensates for the limited temporal and spatial coverage of the MISR AOT. The comparison of the AERONET AOT with the estimated AOT indicates that the OMI aerosol index is a good surrogate for estimating AOT over these dust-dominated regions. The comparison results are better than with either the Deep Blue AOT or OMI-retrieved AOT. The estimated AOT values are then used to examine radiative impacts of aerosols in conjunction with broadband measurements from CERES top of atmosphere fluxes. The shortwave CERES flux appears not to show an obvious response to the estimated AOT. The longwave flux, on the contrary, decreases with increasing AOT and is shown to be a function of surface and atmospheric physical parameters.
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