Investigation of glacial isostatic adjustment in Dronning Maud Land, East Antarctica, using long-term GNSS observations

Global Navigation Satellite System (GNSS) data provide critical insights into solid Earth deformation. GNSS observations at bedrock in glaciated areas like Antarctica serve as essential constraints to model the glacial isostatic adjustment (GIA). Likewise, they may serve to aid the empirical estimation of GIA and of ice-mass balance. Since the last International Polar Year 2007/08, GNSS coverage has significantly been expanded in West Antarctica, the Antarctic Peninsula, and parts of Victoria Land. In East Antarctica, however, logistical challenges and sparse bedrock outcrops have limited the establishment and (re-)observation of new GNSS stations.

In order to address this gap, a GNSS network of mostly episodic site was deployed across western and central Dronning Maud Land, East Antarctica. Measurements were initiated in the mid-1990s while the most recent observation campaign was conducted during the 2022/2023 Antarctic season. Additionally, two new permanent GNSS sites were installed in western Dronning Maud Land in the beginning of 2020.

This study presents results from a consistent analysis of both episodic and continuous GNSS datasets over a time span of more than 20 years. We demonstrate how this extended temporal coverage enhances the accuracy of secular trends derived from GNSS time series. To isolate the GIA displacement signal, we account for elastic displacement caused by present-day ice mass changes using satellite altimetry and surface mass balance models. The resulting trends are compared to GIA estimates inferred from a number of models. Thus, we come up with new insights into the deformation pattern in a region that lack respective information so far. Our findings emphasize the importance of long-term GNSS measurements in refining GIA models for East Antarctica.