Applied DInSAR Analysis to Crustal Deformation along Greenland’s Northwestern Coasts
Bedrock displacements on Greenland’s coasts are expressions of both climate-driven elastic responses and long-term viscous responses originating from the mantle. Such patterns have been observed by the Greenland GPS Network (GNET), but the limited number of sites precludes a more in-depth analysis of the spatial variability of these processes. The remote nature of this region means that conventional in situ data for such trends is difficult to acquire. Differential Interferometric Synthetic Aperture Radar (DInSAR) is a satellite-based remote sensing technique that allows for a cost-effective means of monitoring surface displacements at sub-centimeter levels with broad spatial coverage. Synthetic aperture radar (SAR) images can be taken at regular intervals, during the polar night and are not affected by clouds. DInSAR studies provide insight into deformation trends that span many years. Recently, the Geology Survey of Norway released a mapping service (insar.ngu.no) that uses DInSAR techniques to assess ground deformation such as subsidence, landslides and rockslides while also quantifying changing city infrastructure (Dehls et al., 2019). In this study, we create a similar surface deformation map for the coast of northwest Greenland using DInSAR techniques and C-band SAR data from the European Space Agency’s (ESA) Sentinel-1A/B satellite. We use 78 descending (Path 26) images spanning December 2015 to May 2018 to generate high-coherence interferograms that showed vertical deformation in this region over glacial ice and bedrock. Using the Small Baseline Subset (MSBAS) methodology, we generate a deformation time series that can be validated using corresponding GNET data from nearby sites. We can use our spatially dense broad observations to examine short wavelength variability in deformation while also identifying geophysical loads and processes that result in crustal deformation.