Millimeter-wave measurements and analysis of snow-covered ground

Modeling of Millimeter Wave Backscatter of Time-Varying Snowcover

“…However, these ground truth measurements are usually laborious and thus very difficult to acquire as time series. Several experiences have been reported in the literature on the millimeter wave interaction with snowcover [8][9][10][11][12][13] and the diurnal variation of radar signatures of snow [14][15][16]. Although these investigations indicate that the backscatter of snowcover is strongly influenced by the presence of liquid water, electromagnetic modeling of snow undergoing internal changes, due to metamorphism and phase change, still lacks a systematic study.…”

Millimeter Wave Measurement and Modeling of Terrain Scattering

“…Although several papers have appeared recently documenting the results of millimeter-wave (MMW) radar observations of snow-covered terrain [Stiles and Ulaby, 1980;Ulaby and Stiles, 1980;Hayes et at., m4;Hallikainen, 1985;Baars and Essen, 1988;Currie et aL, 1988;Narayanan and Mclntosh, 1990], the interaction mechanisms responsible for the observed radar response are not well understood at the present time. At millimeter wavelengths, snow is a highly lossy medium, particularly when wet; consequently, the penetration depth is only of the order of a few centimeters [Ulaby et aL, 1986[Ulaby et aL, , p. 1608Hallikainen, 1985;Hallikainen et aL, 1986].…”

Estimation of surface snow properties using combined millimeter-wave backscatter and near-infrared reflectance measurements

“…Measurements show varied effects: one study shows that snow backscatter increases with surface roughness [21], whereas another study shows a slight lowering in backscatter with increasing roughness [19]. A third study observed that the backscatter decreased for dry snow, but increased for wet snow with increasing roughness [22], while a fourth study concluded that the backscatter decreases with roughness at incidence angles of less than 35° , while this trend was reversed at higher incidence angles [23]. Our conclusion is that there is a weak dependence of snow backscatter at millimeter wavelengths on surface roughness.…”