Ground-penetrating radar measurements of 64 Austrian glaciers between 1995 and 2010

The ongoing retreat of mountain glaciers necessitates the development of future scenarios of glacier runoff. These scenarios are not only governed by future climate scenarios influencing glacier mass balance but also by the glacier volumes, which are subject to melt. Ground-penetrating radar (GPR) is a valuable tool for measuring the thickness of mountain glaciers, although ground-based measurements are labour-intensive, so not all glaciers can be surveyed. This study presents the results of GPR surveys on 64 Alpine glaciers, carried out between 1995 and 2010. The glacier areas range from 0.001 to 18.4 km(2), and their ice thickness was surveyed with an average density of 36 points km(-2). The point measurements were extrapolated manually to derive volume maps. The mean ice thickness varies between 10 and 92 m; the maximum ice thickness is about three times the mean thickness. According to the glacier state recorded in the second glacier inventory, the 64 glaciers cover an area of 223.3 +/- 3.6 km(2), with a mean thickness of 50 +/- 3 m and a glacier volume of 11.9 +/- 1.1 km(3). The mean maximum ice thickness is 119 +/- 5 m.