Modeling of Volume Scattering in Bicontinuous Random Medium for Remote Sensing of Terrestrial Snow from 4 to 18 GHz

In this paper, we study the snow aggregation and its effects on the frequency dependence of snow volume scattering from C to Ku band (4-18GHz) with the bicontinuous model. The snow microstructures are modeled by the bicontinuous model. The snow size distribution and aggregation are quantified by the bicontinuous correlation function which then gives the spectral density of snow. The phase matrix of snow is derived from the volume integral equation based on the Born approximation (BA). The phase matrix is proportional to the spectral density of snow. Finally, the scattering coefficients are expressed in terms of the phase matrix. The results show that snow with more aggregation has faster decay spectral density leading to a weaker frequency dependence than that of Rayleigh scattering from C to Ku band. The scattering coefficients computed with BA, and the numerical solution of Maxwell equation in 3D (NMM3D) gives similar frequency dependence of ~2.6 power. In addition, scattering coefficients of BA and NMM3D are also in good agreement from X to Ku band.