Multi-layer model simulations of backscattering and emission from snow covered soils

In this paper an overview of experimental and theoretical investigations concerning snow cover by using both active and passive microwave sensors will be presented. In particular, the effects of multi-layer structure of snowpack and its temporal evolution on backscattering and emission have been investigated by model simulations based on the Dense Medium Radiative Transfer (DMRT). The implemented model has been validated using both X- band Cosmo SkyMed acquisitions and multi-frequency microwave radiometric data collected in the winters between 2007 and 2011 on a test area located in the Eastern part of the Italian Alps, and corresponding direct measurements of the main snow parameters. The effect of snow parameters on microwave backscattering at X- band and emission at X-, Ku- and Ka-bands has been analyzed by comparing experimental data and model simulations performed with a multi-layer version of the DMRT-QCA model. The study has been focused on the effect of layering structure of snowpack typical of the Alpine regions. It has been observed that the multi-layer model is generally able to account for the effects of complex stratigraphy, reproducing the measured backscattering and emission with a higher accuracy than the single layer one.