Aerosol optical thickness retrieval over land and water using SCIAMACHY/GOME data

An algorithm for the retrieval of the aerosol optical thickness over land and over water from SCIAMACHY (SCanning Imaging Absorption SpectroMeter for Atmospheric ChartographY) is presented. Because calibrated data are not yet available for the SCIAMACHY channels used by the algorithm, the concepts were tested with GOME (Global Ozone Monitoring Experiment) data. The cloud fraction in the GOME pixels has been determined using the FRESCO (Fast Retrieval Scheme for Clouds from the Oxygen A Band) algorithm. Surface contributions to the TOA reflectance are determined from the GOME surface reflectance database [1]. The aerosol retrieval algorithm uses Look Up Tables (LUT) that were created using the radiative transfer model 6S. The algorithm allows for the retrieval of aerosol types characterized by Angstrom coefficients in the range from -0.1 to 2.8. Comparison of the results with AERONET sun photometer data for 12 sites in Europe and Africa shows very good agreement.