Vol. 4, No. 2, 139-149, 2005

Abstract
The extraordinarily hot summer of 2003 caused record-breaking glacier melt in the European Alps (i.e. eight times the long-term average). Multispectral Landsat Thematic Mapper (TM) satellite data of August 2003 clearly shows very dark glacier ablation areas, particularly in the near-infra­red. In order to assess the influence of the low glacier albedo and the special 2003 meteorological conditions on glacier mass balance more quantitatively, we have calculated glacier albedo from TM for three distinct years (1985, 1998, 2003) and applied a distributed glacier mass balance model forced by climatic mean as well as the special 2002/03 meteorological conditions. For this purpose, we use the TM-derived albedo for 1998 and 2003 as a surrogate for the background glacier albedo. We observe a large albedo variability from year to year, constant or even decreasing albedo with altitude and much lower albedo values in the ablation area than generally applied (0.15 instead of 0.35). The modelled mass balance reveals a distribution pattern that is governed by the potential solar radiation, increasing glacier mass loss with altitude using the 2003 albedo, and a three times higher mass loss for the meteorological conditions of 2002/03 compared to the climatic means.

ISSN 1729-3782