Snowmelt evolution mapping using an energy balance approach over an alpine terrain

Abstract

A computer model simulating snowmelt evolution and the spatial snowmelt pat- tern using an energy balance approach over an alpine terrain was developed. With a digital elevation model (DEM), surface characteristics information and meteo- rological data as input, all radiation balance components, turbulent fluxes, precip- itation, and finally snowmelt were modeled on a daily basis. Special emphasis was given to snow redistribution. The model was applied to an area of 35 km² in the Schilthom Massif (Bernese Oberland, Switzerland) for 1996-97. The model calculations are compared with a snowmelt evolution map, which was produced by combining seven scenes of aerial photographs taken in the Bernese Alps during the melting season 1997 (March-September). Both the temporal comparison of the snowmelt evolution and the spatial comparison of simulated and observed snowmelt patterns show a good accordance: at any of the compared dates, spatial coincidence is equal to or better than 78%. It can therefore be concluded that the model supplies a quite realistic reproduction of the energy exchange processes taking place at the ground snow-cover/atmosphere interface during winter and spring.