A distributed surface energy-balance model for a small valley glacier .1. Development and testing for Haut Glacier d'Arolla, Valais Switzerland

This paper describes the development and testing of a distributed surface energy-balance model used to calculate rates of surface melting at Haut Glacier d'Arolla, Valais, Switzerland. The model uses a digital elevation model (DEM) of the glacier surface and surrounding topography together with meteorological data collected at a site in front of the glacier to determine hourly or daily totals of the energy-balance components and hence of melting over the entre surface of the glacier with a spatial resolution of 20 m. The model can also be used to determine temporal and spatial variations in snow depth, snow-line position and glacier surface albedo. Calculations from the model are compared with observations made along the glacier centre line in 1990, and in general the model performs very well. The correlation coefficient between calculated and measured snow-line elevation, albedo and ablation are 0.99, 0.85 and 0.81, respectively. The main source of error between modelled and measured values of these variables is probably inadequacies in the parameterization of albedo used in the model.