Numerical Investigation on the Effect of the Snowpack Surface Roughness on the Radar Echo

The backscattered signal collected by space-born radars, such as Sentinel-1, for area covered by snow is affected by the condition of the snow itself, in particular during melting. However, the potential evidence of a relationship between the different melting phases and the amplitude of the backscattered signal still remains a difficult phenomenon to be described quantitatively. This paper proposes a preliminary approximated model, built upon i) a first-order simulation based on plane-wave incidence on stratified media that account for the bulky physical parameters of the snowpack, such as depth, liquid water content, density, and ii) a full-wave simulation to include the effect of the surface roughness. The model is tested against experimental data for a site in the Italian Alps (Malga Fadner), where data from Sentinel-1, as well as in-situ data about the composition of the snowpack, are available for the winter season 2017/18, showing good general agreement.