Comparison of digital elevation models of alpine glaciers

Glaciers are indicators of the global climate change. The change in the extent and volume of a glacier can be estimated from digital elevation models (DEMs) produced from remotely sensed spaceborne or airborne data using photogrammetric, interferometric, or laser scanning techniques. For this study, the most promising data sources available were selected and tested. The selected sites were two alpine glaciers, Hintereisferner valley glacier in the Central Eastern Alps in Austria and Svartisen ice gaps in Northern Norway. The data included very high resolution optical images of the Ikonos and Eros satellites, aerial photographs and airborne digital camera images, spaceborne and airborne radar images, airborne laser scanner data, terrestrial photographs and ground control points and profiles measured with GPS equipment. The objective was to find out which data and method would yield the most accurate result by comparing the different DEMs generated from data acquired as simultaneously as possible. Methods were also developed for estimation of accuracy of change in the volume of a glacier between two time instants.