Dense media radiative transfer theory based on quasicrystalline approximation with applications to passive microwave remote sensing of snow

Dense media radiative transfer (DMRT) equations based on quasicrystalline a pproximation (QCA) for densely distributed moderate size particles are deve loped. We first compute the effective propagation constant and coherent tra nsmission into a dense medium on the basis of the generalized Lorentz-Loren z law and the generalized Ewald-Oseen extinction theorem. The absorption co efficient of the dense media is then calculated. The distorted Born approxi mation is next applied to a thin layer to determine the bistatic scattering coefficients and the scattering coefficient. The phase matrix in DMRT is t hen obtained as bistatic scattering coefficient per unit volume. The model is applied to multiple sizes and for sticky particles. Numerical results ar e illustrated for extinction and brightness temperatures in passive remote sensing using typical parameters in snow terrain. The QCA-based DMRT is als o used to compare with satellite Special Sensor Microwave Imager (SSM/I) br ightness temperatures for four channels at 19 and 37 GHz with vertical and horizontal polarizations and for two snow seasons. It shows reasonable agre ement to snow depth of 1 m.