Observations on glaciers in the eastern Austrian Alps using satellite data

Abstract

Ground-based measurements on the Pasterze Glacier and the Kleines Fleisskees, located in the eastern Alps of Austria, have shown that these glaciers have receded significantly. Landsat Thematic Mapper (TM) data of these glaciers were acquired in August of 1984,1986,1988 and 1990, and have been studied in detail. The 1984–1990 retreat of the Pasterze Glacier has been measured using digital TM data, but the 1984–1988 retreat of the Kleines Fleisskees has not been observed using the TM data because the magnitude of recession between 1984 and 1988 was small relative to the resolution of the TM data. Significant increases in the area of exposed ice (icc facies) on both the Pasterze Glacier and the Kleines Fleisskees were observed and measured using TM data acquired in early August from 1984 to 1988. The area of the Pasterze Glacier and Kleines Fleisskees basins, as measured using TM data, is 20·8±1·02km² and 1·56±0·188 km², respectively. The percentage of the Pasterze Glacier comprised of bare ice increased from 23 per cent in August of 1984 to 36 per cent in August of 1988. Data from nearby meteorological stations show no significant new snowfall during the months of July and early August in 1984, 1986 or 1988 prior to the Landsat overpasses, to obliterate the delineation of the ice facies. The Kleines Fleisskees was also measured using the same TM scene. 40 per cent of this glacier consisted of the ice facies in 1984, and 59 per cent in 1988. Field measurements show that both the Pasterze Glacier and the Kleines Fleisskees have been losing mass for more than 100 years.