SAR tools for snowmelt modelling in the project HydAlp

A procedure for mapping melting snow areas is described which is based on change detection methods. The algorithm was applied for snow mapping in alpine drainage basins and on glaciers, using ERS SAR images. The comparison with snow maps from Landsat Thematic Mapper images shows in general good agreement. Differences are observed mainly in areas with patchy snow cover where SAR tends to underestimate, and Landsat to overestimate, the snow extent. The developed software aims at operational generation of SAR snow maps for snowmelt runoff forecasting