Image-based correction of the aerosol effect over coastal waters with ASTER VNIR data

ABSTRACT: The use of satellite remote sensing data for physical measurements of the Earth’s surface requires the removal of the atmospheric contribution from the signal recorded at the sensor, a process usually called atmospheric correction. This task becomes more critical when the signal originating in the atmosphere dominates over the signal due to the surface itself, as is the case of remote sensing over ocean in the visible and near-infrared (VNIR), because of the very low water reflectance. A method is proposed to estimate the effects of the aerosols on the VNIR ASTER (Advanced Thermal Emission and Reflection Radiometer) bands 1 and 2, based on the selection of a suitable aerosol model (from a predefined set of candidates) and estimation of the aerosol optical thickness. This is achieved through the use of VNIR band 3 (760– 860nm) dual-viewing geometry, for which the water-leaving reflectance is assumed to be null. The optical properties of the aerosol models are simulated using the 6S Radiative Transfer Code (RTC), which is also used to perform all the radiative transfer calculations. The method is described and tested with simulated ASTER data. 1