Using ASTER and SRTM DEMs for studying geomorphology and glaciation in high mountain areas

For selected peaks in high mountains of diverse climatic regions (Andes, Hindu Kush, Tien Shan) digital elevation models (DEMs) have been generated from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data using PCI Geomatica 8.1/8.2 software. Artifacts in the ASTER DEM were eliminated using data from the Space Shuttle Radar Topography Mapping mission (SRTM). For two of the four case studies, accuracy was evaluated by comparison the ASTER/SRTM DEM with DEMs derived from contour maps. Whereas the SRTM DEM shows correct elevations in all altitudes, elevations in the ASTER DEM are slightly to low in higher altitudes and south-exposed aspects. Geomorphic analyses were undertaken using the software ArcInfo, ArcView and SAGA. Cluster analyses including tangetial, vertical curvature and slope combined with spectral information helped identifying debris-covered glaciers and geomorphologic forms and processes. Results show that ASTER/SRTM DEMs are useful for an interpretation of the macro- and mesorelief. The DEM scale sets limits for the level in analysis detail. Whereas SRTM DEMs offer more precise elevations, ASTER DEMs offer more geomorphologic details.