An atmospheric correction procedure for the ATSR-2 visible and near-infrared land surface data
An atmospheric correction procedure for the solar reflecting channels of the Second Along Track Scanning Radiometer (ATSR-2) is described in which the aerosol optical thickness is retrieved from atmospheric simulations using the top-of-atmosphere (TOA) reflectances. The aerosol optical thickness is obtained when the ratio of the corresponding surface reflectances, in the off-nadir view to the nadir view, for two selected sensor channels, are equal. Directional reflectance models have been used to determine the validity of this approach and to determine suitable channel combinations. Simulations of the procedure for realistic surfaces indicate the retrieval of tau A 550 is better than 0.1 when the aerosol meteorology is known. The accuracy of the retrieval of surface reflectance is significantly affected by deviations from the expected aerosol meteorology. Factors affecting the accuracy of the correction procedure are described.