On the Use of Sentinel-1 to Study Snow Melt Dynamics in a Glacierized Mountain Catchment

Snow and glaciers play a crucial role in various environmental services in hydrology and climate, and also regarding hazards assessment related to snow and ice avalanches. SAR imagery is particularly useful for studying snow and glacier-related issues: it is insensitive to the cloud cover and is sensitive to some snow/glacier properties such as liquid water content. In this study, we focus on the snowmelt dynamics in the catchment of the Saint-Sorlin Glacier in the French Alps using SAR images in C-bands from Sentinel-1. Our objective is to gain a better understanding of the snow and ice melt processes in a glacierized catchment by monitoring the spatial and temporal variability of the SAR signal on the glacier (ablation and accumulation areas) and outside the glacier, and comparing it to fractional snow and ice maps from Sentinel-2 spectral unmixing. We are able to identify key melting phases using SAR backscatter time series. The set of melting phases are compared with the ones estimated from liquid water content and snow water equivalent simulations made with the snowpack model Crocus.