AATSR Satellite Aerosol Retrievals during the 2004 United Arabic Emirates' Unified Aerosol Experiment (UAE2)

This contribution addresses the satellite mission objectives of the United Arabic Emirates - Unified Aerosol Experiment (UAE2) during August and September 2004. Aerosol properties were retrieved using data from the AATSR instrument onboard the European ENVISAT satellite. The dual view algorithm was applied over land and the single view algorithm over the ocean. Both algorithms have been merged into a fast and efficient algorithm that allows for near real-time processing and which is suitable for semi-operational use. It includes all necessary corrections for surface and atmospheric effects including fully automated cloud screening procedures. The algorithm can be applied to retrieve the aerosol optical depth (AOD) at 4 wavelengths, the Angstrom coefficient (describing the spectral variation of the AOD and is an indicator for the slope of the aerosol size distribution) and the mixing ratio of dominant aerosol types. The AATSR retrieved AOD compares favorably with collocated AERONET. Over the ocean the regression coefficient is 0.78, with a small bias toward higher values for the AATSR data. Over the desert there is a slight underestimate and the regression coefficient is 0.57 (preliminary results). Comparisons with aerosol optical depth from other satellite instruments are also shown.