Retrieval of aerosol optical depth and single scattering albedo from AMTIS imagery

The Airborne Multi-angle TIR/VNIR Imaging System (AMTIS) samples the surface at a number of view angles and offers the potential of retrieval of atmospheric aerosol properties, land surface bidirectional reflectance etc. This paper presents the retrieval algorithm of aerosol optical depth and single scattering albedo from visual and near-infrared bands of AMTIS based on a simplified path radiance model. Atmospheric parameters such as molecular scattering and absorption are calculated using MODTRAN4. Under the assumption that the aerosol optical depth above the sensor is not affected by the surface, the aerosol optical depth above the sensor (4.2 km) is also calculated using MODTRAN4. The path radiance is divided into two components: the singly scattered radiance and multiple-scattering radiance. The AMTIS images acquired on April 11, 2001 in the Shunyi experiment are used in the retrieval. The algorithm performs best over dark surfaces, such as water. The retrieved aerosol optical depth is close to the result from the synchronous Sun photometer data with an error about 0.05∼0.1. Retrieved single scattering albedo is very close to that of the continental aerosol model of 6S.