Definition of ICESat Selection Criteria for Their Use as Height References for TanDEM-X

Abstract

The TanDEM-X satellite synthetic aperture radar (SAR) mission, which is the result of the partnership between the German Aerospace Center (DLR) and Astrium GmbH, has the goal to deliver a high-precision global digital elevation model (DEM). The X-band SAR interferometry-derived DEMs contain absolute and relative height errors that have to be minimized with the help of height references in order to achieve the specified accuracies. ICESat laser altimetry data are suited for this task, due to their accuracy and global distribution. In order to gain experience in the comparison between a radar-derived DEM and ICESat GLA14 elevation data, an X-band DEM was acquired over a test region with the experimental airborne radar system of DLR in Oberpfaffenhofen. Additionally, a laser DEM of the area was used to verify the height accuracy claimed by previously published ICESat studies over different terrain types and after applying different selection threshold criteria. The analyses described in this paper are the basis for the definition of a suitable global ICESat selection strategy and include the computation of the density of selected ICESat samples over the Earth. These aspects are crucial for a successful TanDEM-X DEM generation.

Growth of the Sayram Lake and retreat of its water-supplying glaciers in the Tianshan Mountains from 1972 to 2011

“…GLA System elevations are referenced using the Topex/Poseidon ellipsoid and EGM96 geoid. ICESat/GLA14 data have high vertical accuracy: about 0.1 m (1σ) for flat bare locations and 1 m (1σ) for undulating vegetated surfaces (González et al, 2010). The attained accuracy can reach 0.1 m for monitoring lake elevation in this study.…”

The Delineation of Paleo-Shorelines in the Lake Manyara Basin Using TerraSAR-X Data

“…A morphology preserving multidirectional Lee Filter for noise and artifact reduction was applied [53]. High accuracy ICESat altimetry data from 15 overpasses over Lake Manyara between 2003 and 2009 were processed to calculate a mean lake level of 954.25 m (EGM96, standard deviation of 35 cm) [57]. The SRTM-X lake level was adjusted to this height.…”

Recent Landslide Movement in Tsaoling, Taiwan Tracked by TerraSAR-X/TanDEM-X DEM Time Series

“…A considerable number of studies have been conducted based on TSX/TDX data. For example, 3D topographic reconstruction, fusion of ascending and descending images, phase unwrapping and filtering [28][29][30][31][32], large-scale deformation monitoring e.g., volcano and glacier [33][34][35], relative and absolute accuracy assessment of TSX/TDX DEM [36][37][38][39][40][41], terrain classification and forest height and biomass inversion [42,43]. The accumulated TSX/TDX image pairs acquired over the years can be used to generate a set of DEMs over the same area, which is particularly helpful for investigating the temporal evolution of natural hazards, e.g., landslides.…”