Energy balance calculations on and near the Hintereisferner (Austria) and an estimate of the effect of greenhouse warming on ablation

Abstract

During some 10 days in July 1986, measurements of meteorological variables and ablation were made at two sites on and near Hintereisferner (Austria), namely at GLACSTAT (2500 m), located on the glacier tongue, and at ROCKSTAT (2440 m), just in front of the tongue. In this paper energy balance calculations for both stations are presented. About 90% of the ablation energy at GLACSTAT came from radiation. This large value is a consequence of the low albedo (0.16) and the long periods of sunny, relatively cold weather. A detailed comparison is made of the surface energy budget at the two sites. While melting is important at GLACSTAT, the loss of energy by the turbulent fluxes and the outgoing long wave radiation is larger at ROCKSTAT. Finally, the consequences of the rising concentrations of atmospheric trace gases on ablation are discussed. The data from GLACSTAT will be adapted to estimated past and projected future concentrations. If all relevant trace gases are considered and under the specific conditions of the experiment total ablation for the 10-days period will increase by 11% in the 50 years after 1986.