We present in this paper a method which allows us to derive the aerosol optical thickness over land surfaces from satellite data by using the blurring effect due to the scattering. By assuming the ground reflectance to be constant, variations of the satellite signal may be attributed to variations of the atmospheric optical properties. The time evolution of the structure function then allows us to infer the aerosol content over land surfaces. The method was applied to Saharan aerosols, which represent the most important contribution to the atmospheric aerosol loading. The results derived from Thematic Mapper data proved to be in good agreement with simultaneous ground-based measurements. Therefore the method seems able to provide the aerosol contents during Saharan dust events. ¿ American Geophysical Union 1988