POLARIMETRIC BACKSCATTER FROM FRESH AND METAMORPHIC SNOWCOVER AT MILLIMETER WAVELENGTHS

This paper presents 35, 95, and 225 GHz polarimetric radar backscatter data from snowcover. It compares measured backscatter data with detai led in situ measurements of the snowcover including microstructural an isotropies within the snowpack, Observations of backscatter were made during melt-freeze cycles, and measurable differences in the normalize d radar cross section between older metamorphic snow and fresh low-den sity snow were observed, In addition, these data show that the average phase difference between the copolarized terms of the scattering matr ix, S-vv and S-hh, is nonzero for certain snow types. This phase diffe rence was found to be related to snowpack features including anisotrop y, wetness, density, and particle size, A simple backscatter model bas ed on measured particle size and anisotropy is found to predict the Mu eller matrix for dry snowcover with reasonable accuracy.