Results from model comparisons with ERS-1 and field data for snow water equivalent estimation

An operational methodology for monitoring snow cover, particularly snow water equivalent (SWE), for a given watershed by merging information coming from RADARSAT images, snow surveys and a hydrological model is under development at INRS-Eau. A first model, which links the scattering coefficient to the physical parameters of the snow cover and the underlying soil has been developed. However, in order to understand better the various processes and their relationships, it was found necessary to apply more specific and detailed models describing each of the processes identified in that general model. A snow accumulation and melt model is being used to simulate the temperature profile both in the snow cover and in the underlying soil, as well as the density and particle diameter of the snow layers. Surface scattering from agricultural surfaces is also being modeled by one of the three usual models (small perturbations, physical optics or geometrical optics) depending on surface roughness. Finally, volume scattering from the snow cover as well as attenuation of surface scattering by snow cover are also investigated by a model. Results from those models are discussed with comparisons between ERS-1 and field data