Measuring Volume Changes of Alpine Glaciers with SRTM and TanDEM-X Data

Interferometric radar data (InSAR) offer the capability of measuring and monitoring the surface topography of glaciers and ice caps at high accuracy. Of particular interest are single-pass spaceborne InSAR systems such as X-SAR and the satellite formation TerraSAR-X (TSX)/TanDEM-X (TDX) because they are not affected by temporal decorrelation and changes in the atmospheric phase delay. The German-Italian dual antenna radar sensor X-SAR operated in February 2000 on the Shuttle Radar Topography Mission (SRTM), acquiring data over swath of 50 km width, mapping about 40 per cent of the land masses between 60°N and 56°S. SRTM/X-SAR delivered DEM data at slightly better relative vertical accuracy (6 m) and horizontal resolution (30 m) than the SIR-C sensor which also operated on SRTM but provided full area coverage. In June 2010 TDX was launched, flying in close formation with TSX, both forming a single-pass InSAR system with the objective of providing a global DEM with 12m × 12m horizontal sampling and