Measurements of surface deformation of ice sheets in antarctica using TanDEM-X data

The feasibility of utilizing TerraSAR-X/TanDEM-X bistatic SAR interferometry to monitor surface height variations was investigated. The study area was near the terminus of Thwaites Glacier where surface roughness and steep slope prevent satellite altimetry from measuring in high precision. Due to a lack of reliable DEM in this region, the absolute phase offset correction was not carried out in the absolute surface height conversion. Instead, the relative height difference between two unwrapped interferograms was computed. It was assumed that any signal other than the estimated pattern of the absolute phase offset, which is a constant in phase, could be the topographic variation. Two pairs of TanDEM-X data with 28 and 11 days of temporal differences were acquired in 2011 and 2012, respectively. The results show some surface height variations especially in the fast moving and heavily crevassed areas and a possible sign of surface subsidence in front of the crevasse forming area.