Subproject 6: Glacial isostasy, mass balance & dynamics of the Greenland ice sheet
Subproject 6 "Glacial isostasy, mass balance and dynamics of the Greenland ice sheet" aims to determine the glacial-isostatic equilibrium motion (GIA) of the Earth's crust in northeast Greenland. The knowledge of this process is presently associated with a very high uncertainty, which results in substantial inaccuracies regarding the derivation and interpretation of the ice mass balance and dynamics of the Greenland ice sheet as a whole, and in particular with respect to the drainage basin of the northeast Greenland Ice Current. The direct geodetic determination of the GIA effect is carried out by means of ground-based GNSS measurements on bedrock. The measurements are linked to observations of earlier periods and complemented by international cooperation with permanent GNSS measurements. These measurements provide the only means to determine the GIA effect in situ and to detect seasonal effects in addition to the derivation of a long-term trend. The combination of satellite-based techniques (satellite gravimetry and altimetry) provide additional means to determine the GIA effect and the recent ice mass change, and the results of both methods can be compared. The addition of satellite remote sensing data (Landsat-1 to 8) to derive time series of the velocity fields and the conditions of the outflow and peripheral glaciers in the working area will overcome the limitation of spatial sampling in satellite altimetry. This enables us to separate surface mass balance effects from those of ice dynamics. Finally, we contribute to the study of tidal dynamics through kinematic GNSS measurements near the front of the 79-degree glacier.