Theoretical and Experimental Studies of Snow Covers Microwave Emissivity

Microwave radiometers, operating at 3.95, 19.5, 37.5 and 150 GHz and placed in a tower, were used for snow measurements during the winters of 1985-1989. The effects of snow structure, wetness, and grain size were examined in detail. The emissivity of snowpack has been calculated by a quasi-static method and by applying the equation of radiative transfer. The latter takes into account the physical-mechanical properties of the real snowpack obtained by direct glaciological methods. The experimental data are compared against theoretical results. The quasistatic model is shown to be adequate for f < 20 GHz whereas the radiative transfer model agrees for f < 150 GHz, especially when the size distribution of ice particles in snow is included.