Modelling alpine permafrost distribution based on energy-balance data: a first step

The computer model PERMEBAL (which stands for Permafrost and Energy Balance) simulates the persistence of snow cover and daily ground surface temperatures of snow-free gridpoints. It was developed for high-mountain conditions. The model describes different vertical energy fluxes at the surface. With meteorological and site-specific input data, PERMEBAL delivers daily ground surface temperatures of snow-free gridpoints. Special emphasis is given to simulation of snow-cover development (snow fall, snow redistribution, snowmelt). The resulting ground surface temperature data are intended for use as input data for future ground heat flux simulations. The aim is to model ground thermal conditions and thus permafrost distribution. The model was applied to the Corvatsch-Furtschellas area (16 km², Engadin, eastern Switzerland). The results show that the area could be divided into three classes of mean annual sums of daily ground surface temperatures of snow-free pixels, similar to ‘permafrost probable’, ‘permafrost possible’ and ‘permafrost improbable’ classifications used in earlier empirical permafrost distribution models