Model for land surface reflectance treatment: Physical derivation, application for bare soil and evaluation on airborne and satellite measurements

Abstract

For land surfaces and atmospheric aerosol characterization on the basis of satellite and airborne measurements models for surface reflection description are required. At present time for visible and infrared spectral regions semi-empirical model for surface reflection are usually used for these purposes. Due to the lack of physical basis, these models introduce a lot of uncertainties into the problem of aerosol and surface properties retrieval. In this paper we consider the possibility of using physically based models for bidirectional reflection matrix (BRM) which can be applied to the problem of simultaneous retrieval of aerosol and land surface properties. The physical model for the BRM is derived from the general solution of the electromagnetic scattering problems by random media. The equation for the reflection matrix is obtained within the far-field approximation when the ladder scattering diagrams are taken into account. To perform analytical averaging over orientation of the surface elements we assume that at different scales the surface can be considered as the Gaussian surface. We use multi-angle photopolarimetric airborne measurements of the Research Scanning Polarimeter (RSP) and satellite POLDER (Polarization and Directionality of the Earth's Reflectances) measurements to investigate the performance of the presented BRM model. The results of the comparison are discussed.