Microwave polarization characteristics of snow at 6.9 and 18.7 GHz: Estimating the water content of the snow layers

摘要

Theoretical and empirical tools for the exploration of the radio-thermal radiation of the snow cover in C and K-bands are developed taking into account the method of polarization measurements of the integral reflection coefficient of a snow layer. In addition, experimental in-situ measurements were performed at 6.9 and 18.7 GHz using a new portable optical system. The analyses of the measurements showed that the difference in polarization increases by increasing the thickness of the snow layer according to its physical characteristics. The study of reflection coefficient of the snow layer includes volumetric diffusion and coherent components determined by effective dielectric conductivity and volumetric scattering. The results showed that the value of the effective dielectric conductivity depends on the correlations between the roughness parameter and the wavelength, and increases with the growth of crystal size, as shown by the increase in the polarization difference when the size of the snow grains is increased. Moreover, the reflection coefficient was found to depend weakly on the polarization irradiance. The calculated snow depths and snow water equivalents are in a very good agreement with the observations made. (C) 2019 Elsevier Ltd. All rights reserved.