Space-based Interferometric Synthetic Aperture Radar (InSAR) applications have been widely used to monitor the cryosphere over past decades. Owing to temporal decorrelation, interferometric coherence often severely degrades on fast moving glaciers. TanDEM-X observations can overcome the temporal decorrelation because of their simultaneous measurements by two satellite constellations. In this study, we used the TanDEM-X pursuit monostatic mode with large baseline formation following a scientific phase timeline to develop highly precise topographic elevation models of the Petermann Glacier of Northwest Greenland. The large baseline provided the advantage of extracting topographic information over low relief areas, such as the surface of a glacier. As expected, coherent interferometric phases (> 0.8) were well maintained over the glaciers, despite their fast movement, due to the nearly simultaneous TanDEM-X measurements. The height ambiguity, which was defined as the altitude difference corresponding to a 2π phase change of the flattened interferogram, of the dataset was 10.63 m, which was favorable for extracting topography in a low relief region. We validated the TanDEM-X derived glacial topography by comparing it to the SAR/Interferometric radar altimeter observations acquired by CryoSat-2 and the IceBridge Airborne Topographic Mapper laser altimeter measurements. Both observations showed very good correlation within a few meters of the offsets (-12.5~ -3.1 m), with respect to the derived glacial topography. Routine TanDEM-X observations will be very useful to better understand the dynamics of glacial movements and topographic change.
Bibliographical noteFunding Information:
Funding: This research was funded by the Korea government (MSIT) and supported by the National Research Foundation of Korea (NRF) under the Space Core Technology Development Program (project id: 2017M1A3A3A02016234). This study was also supported by the Korea Polar Research Institute (KOPRI) grant PE18120.
Acknowledgments: We would like to thank the German Aerospace Center for access to the TerraSAR-X, TanDEM-X, and global DEM data through the DLR projects (No. XTI_GLAC6649 and DEM_GLAC1184). The CryoSat-2 data provided by the European Space Agency and the ATM data provided by the National Aeronautics and Space Administration are appreciated. This work was supported by Global Surveillance Research Center (GSRC) program funded by the Defense Acquisition Program Administration (DAPA) and Agency for Defense Development (ADD).
© 2018 by the authors.
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)