Emissivity peculiarities of the inland salt marshes in the south of Western Siberia

Abstract

ABSTRACTThe presence of water-dissoluble salts in soils leads to a wide variation in soil microwave radiation that makes precise determination of water-physical characteristics of soil using satellite data hardly possible. To assess the effect of soil salinization, the emissivity of salt-affected soils in the Kulunda plain located in the south of Western Siberia was studied. Steppe site and an inland salt marsh (ISM) formed at the bottom of depressions of dried-up salt lakes were the main objects of the research. Both sites are situated in the same natural-climatic conditions and have similar relief. The spatial distribution of the underlying surface brightness temperature was obtained from L1C product of Soil Moisture and Ocean Salinity (SMOS) mission. The diurnal temperature variations of ISM were measured in the course of a daily ground-based experiment to determine the temperature gradients. During the laboratory experiment, we defined the dielectric properties of soil and calculated its emissivity. The comprehensive studies are evidence of great diurnal variation in ISM microwave radiation. The joint use of satellite and laboratory data allows us to specify the contribution of salt-affected soils into total microwave radiation of the underlying surface. The brightness temperature obtained from SMOS and the one calculated from the laboratory dependencies of ISM emissivity on temperature and moisture are in fairly well correlation.