Modeling Microwave Emission at High Frequency from Stratified Snow Using Dense Media Radiative Transfer Theory Based on the Quasicrystalline Approximation (qca/dmrt)

1. ABSTRACT The multi-layer dense media radiative transfer (DMRT) theory based on the quasicrystalline approximation (QCA) has been applied for studying both passive and active microwave remote sensing signatures [1], [2]. It is shown that the layered structure is essential to analyze the microwave emission from snow because high frequency is sensitive to the scattering from the medium top and low frequency is sensitive to the entire snow pack. Compared to those from single layer QCA/DMRT model, multilayer QCA/DMRT model predicts higher polarization difference and weaker frequency dependence of brightness temperatures than a homogeneous single layer snow model. Also, brightness temperatures at 18.7GHz and 36.5GHz from the multilayer model are in better agreement with ground observations. For broader applications of QCA/DMRT, we need to further study simulations at higher frequency and compare with the Ground Based Microwave Radiometer (GBMR) observations of Tb at 89 GHz. Such an extension will benefit the remote sensing of surface properties from Advanced Microwave Sounding Unit-B (AMSU-B), Microwave Humidity Sounder (MHS), Special Sensor Microwave Imager and Sounder (SSMIS), and Global Precipitation Measurement (GPM) Microwave Imager (GPMI). The DMRT theory takes into account the collective scattering effects of the particles by including the wave interactions among the particles [3]. The QCA/ DMRT model gives different results when compared to classical independently scattering theory: 1) The extinction saturates at high fractional volume, 2) The