Retrieval of dust aerosol properties over bright-reflecting desert surfaces with the satellite-borne Medium Resolution Imaging Spectrometer MERIS

Abstract

Retrieving aerosol properties from space-borne platforms above deserts, where the surface reflectance is usually very bright, is a challenging problem. The contribution of surface to TOA (Top-Of-Atmosphere) reflectance can reach values of more than 90%, especially for wavelengths above 500 nm. For this reason, detailed knowledge of aerosol and surface optical properties from desert regions is required to distinguish atmospheric radiation from radiation resulting from surfaces that are intrinsically bright. Detailed radiative transfer calculations have been done in a sensitivity study within this thesis to yield information about the technical and physical feasibility of distinguishing between aerosol-loaded atmosphere and surface.The main purpose of this work is to establish a retrieval technique that yields information about dust aerosol properties over source regions from satellite data. The basic quantity retrieved from satellite measurements is the Aerosol Optical Thickness (AOT).