Geodetic GNSS measurements in north-east Greenland based on Polarstern cruises PS150 and PS156

• Applicant: Dr.-Ing. Mirko Scheinert
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567859092

The Greenland Ice Sheet (GrIS) is sensitive to changes in atmospheric and oceanic conditions which are triggered by climate change. Meltwater entering the ocean affects both global and regional sea level as well as oceanic circulation patterns. On the contrary, warmer ocean water entering Greenland shelf areas may lead to an increased subglacial melting and, thus, destabilisation of the outlet glaciers. Thus, in the period from 2005 to 2015 the GrIS contributed about 20% to the global mean sea level rise, whereby an acceleration in glacier flow accounts for about 50% of the ice-mass loss. However, ice-mass losses and changes in glacier dynamics vary considerably from region to region. In order to gain a better understanding of these interplays and to arrive at reliable projections, we need, on the one hand, records on regional environmental conditions and glaciation history over the Holocene and, on the other hand, a suit of observations on recent changes of the geometry, flow velocity and mass of the GrIS and its individual outlet glaciers as well as of bedrock displacement. The latter is controlled by, and therefore informs about, past and present-day ice-load changes. Moreover, it modulates the geometry of the ice-ocean interface and thereby feeds back to ice mass change processes. A special aspect is given by the hypothesis that an increased ice-mass loss and subsequent vertical rebound may lead to a considerably large seismic activity along the coastal regions. Thus, the main goal of this proposal is to realize geodetic GNSS observations at selected bedrock locations in north-east Greenland to enhance the observational basis for the subsequent analysis of the bedrock displacement. Resulting displacement time series (and rates) will serve as an important constraint to investigate the response of the solid Earth to present-day as well as to past ice-mass changes and, eventually, to refine the modelling of glacial isostatic adjustment. Furthermore, in conjunction with seismic investigations co-located with the GNSS sites we will contribute to the investigation of the nature and causes of present-day seismicity. For this, we will participate in the oncoming cruises of R/V Polarstern to north-east Greenland in 2025 (PS150) and 2026 (PS156). It is planned to visit the locations at Lambert Land West, at Holm Land and, if possible, at Peary Land. At these three locations GNSS campaign measurements shall be realized for one year. At the location Lambert Land West the already existing permanent GNSS site shall be visited for maintenance to ensure a successful continuation of the permanent GNSS recording. Although the detailed treatment of the specific research questions will be subject to a follow-up project proposal, the anticipated field work forms an indispensable prerequisite and will create a crucial foundation for the subsequent investigations.

• DFG Programme: Research Grants