Gravimetric determination of the response of the solid Earth to ice mass changes in southern Patagonia
Alfredo Pasquare (from the cooperation partner AGGO) setting up the FG5 absolute gravimeter at the Estancia Helsingfors measuring point.
Together with the Federal Agency for Cartography and Geodesy (BKG), a research project was launched in August 2019 with the aim of gravimetrically determining the interlinkage between ice-mass changes and the deformation of the solid Earth in the region of the southern Patagonian ice field, .
In previous work, we detected an unusually large crustal uplift in the region of the Patagonian ice fields. This deformation is caused by the response of the solid Earth to past and present ice-mass changes of the ice fields. While the present-day response to past changes is called glacial-isostatic adjustment (GIA), present-day ice-mass changes are responsible for an instantaneous elastic response. Repeated absolute gravimetry provides a geodetic observation technique that has already proven to be extremely suitable for the successful determination of GIA effects in other regions. However, this technique has not yet been used in the region of the Patagonian ice fields. As part of the project, repeated measurements of a regional network consisting of up to eight measuring points will therefore be carried out in three campaigns using an FG5 absolute gravimeter. Gravity changes at the surface will be derived from these measurements. These serve as independent observables of the combined effect of GIA and elastic response and will thus close a gap between satellite gravimetry (data from the GRACE and GRACE-FO missions) and geodetic GNSS measurements. The surface gravity changes will be used for an interpretation together with already derived uplift rates and the satellite gravimetric results. A successful separation of the signals due to the mass change in the Earth's interior and the mass change due to the rapid ice retreat will help to improve the modeling of the solid Earth (the visco-elastic rheology) and to record today's ice mass changes with a higher resolution compared to satellite gravimetry.
As part of the project, a preliminary campaign to explore the potential measurement points took place in October 2019. The actual measurement campaigns were carried out in 2020, 2022 and 2026. Now that the third measurement campaign has been completed, the focus is on evaluating the measurements and interpreting them scientifically.
Project partners on the Argentinian side are the Universidad Nacional de La Plata (UNLP) and the Argentinian-German Geodetic Observatory (AGGO), City Bell. The support of CONICET is also to be acknowledged.
Read more:
- joint press release TU Dresden and BKG Leipzig
- current news Chair of Geodetic Earth System Research
- To the expedition reports
- DFG project GravPatagonia (project leaders: M. Scheinert, A. Rülke)
- Project page at the Federal Agency for Cartography and Geodesy (BKG)
- Instagram: instagram.com/tudresden