Interaction between mass changes of the Antarctic Ice Sheet and solid Earth in Dronning Maud Land, East Antarctica
Dr.-Ing. Mirko Scheinert
Technische Universität Dresden
Institut für Planetare Geodäsie
Professur für Geodätische Erdsystemforschung
With this project we aim to determine the deformation of the Earth’s crust in Dronning Maud Land, East Antarctica, by geodetic GNSS measurements with improved spatial resolution and over a long time span of partly more than 20 years. The response of the solid Earth to present and past ice-mass changes shall be estimated, namely the instantaneous elastic response and glacial-isostatic adjustment, resp., by using up-to-date findings on the rheological structure of the Earth in a consistent way. Finally, we will compare the GIA estimates from GNSS measurements, from a combination of satellite data and from modelling to improve our understanding of the interaction between cryosphere and solid Earth with the focus on Dronning Maud Land.Glacial-isostatic adjustment still exerts the greatest uncertainty when determining the mass balance of the Antarctic Ice Sheet by satellite gravimetry. The only direct measurement of the GIA effect can be obtained by realizing geodetic GNSS measurements on bedrock. As investigated so far, the vertical deformation pattern is not uniform across Antarctica. Dronning Maud Land is one of the areas where comparably small deformation signals are expected but measured so far by only a few geodetic GNSS sites. The applicant’s group already started in 1995 to perform episodic (campaign-style) geodetic GNSS measurements in Dronning Maud Land. These measurements were spatially extended mostly between 2001 and 2005, and cover an area extending roughly from 71° to 75°S and 13°W to 14°E. Most of these sites are situated in the mountain ranges that run parallel to the coast in a distance of 100 to 200 km. Given the long time span of more than ten up to twenty years, it is scientifically reasonable to repeat the geodetic GNSS measurements. We expect to determine the vertical deformation rate (in terms of a linear trend) with a high accuracy of down to a few mm/a. Thus, the GNSS-inferred vertical deformation rates will serve as a constraint for an improved GIA determination. The GIA effect will be estimated in two ways: Firstly, satellite altimetry and gravimetry will be combined to empirically estimate ice-mass balance and GIA. Secondly, by close cooperation with partners from AWI, the 3D rheological structure of the Earth will be revised and, subsequently, introduced into GIA predictions. Special attention will be given to gain a maximum degree of consistency, for instance when using values for the effective elastic lithospheric thickness in both the calculation of the instantaneous elastic deformation and of GIA. Thus, we aim to contribute to the currently ongoing discussion within the scientific community on how the physical processes in the Earth’s interior can be captured in a better way, to learn about their complexity, and to gain an improved understanding of the interaction between ice-mass changes and solid Earth that is reflected by GIA and related sea-level change.
DFG Programme: Infrastructure Priority Programmes
International Connection: Antarctica