ES0701 - Improved Constraints on Models of Glacial Isostatic Adjustment

The main objective of the Action is to place improved constraints on models of glacial isostatic adjustment through the development of state-of-the-art surface velocity measurements with the consequent production of new ice mass change estimates for the major ice sheets.

This Action addresses the current uncertainty in polar ice mass contributions to present-day global sea level rise. The focus is ice mass change signals derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission (2002-present). The ice mass change is derived from gravity-signals, which are contaminated by glacial isostatic adjustment (GIA). However, the GIA signal in the GRACE results currently exceeds the expected Antarctic ice mass balance signal.

GIA models are data poor in polar-regions and new constraints from precise and geographically widespread surface velocity measurements are needed. Whilst surface velocity estimates have been derived in many of the key regions their accuracy and precision is presently too low.

Recent advances (GIA modelling and geodetic observations) indicate that a collaborative approach at this point in time would lead to a significant improvement in GIA model accuracy. Further, additional data in key locations (Antarctic and Greenland) will be added during the International Polar Year (2007-9). These data will be available to the remodeling effort. In this Action leading geodesists and geophysicists from Europe will focus together, to provide improved constraints on GIA models and, hence, on contemporary ice mass balance estimates for Antarctica, Greenland and the smaller ice caps.

Keywords : Glacial isostatic adjustment, ice mass balance, Antarctica, Greenland, geodesy