Snow cover mapping capabilities using RADARSAT standard mode data

In this study, RADARSAT Synthetic Aperture Radar (SAR) images have been analyzsed with the objective of determining the optimum image modes for snow monitoring. A total of 19 Radarsat Single Look Complex (SLC) data were acquired from Heimdalen between March and August, 1997. The Heimdalen area, located in Norway (61 degreesN, 9 degreesE) is a 128 km2 sub-catchment of the Vinstra River ranging in altitudes from 1053 to 1853 in. Most of the area (60%) is above the treeline. In March the snow is dry, in May the snow is starting to melt and in August the area is snow free. Fully calibrated ortho backscattering images have been derived from the SLC SAR data by correcting for the relief distortion and performing radiometric re-calibration using a high precision DEM and knowledge of the imaging and processing geometry A larger contrast between a wet snow cover and bare ground is found for high incidence angle data. The difference in mean backscattering coefficient between wet snow and ground is found to be 6 and 13 dB for June 12 S2 data and 11 June S7 data, respectively The larger contrast between wet snow and bare ground for higher incidence angles are supported by surface scattering model results by assuming wet snow has a smoother surface than bare ground. Temporal analysis shows that backscattering coefficient of dry snow is 2-3 dB lower than for bare ground.