USING GPS AND GRAVITY TO INFER ICE MASS CHANGES  IN GREENLAND

Van Dam, Tonie; Larson, Kristine; Wahr, John; Francis, Olivier

Bulletin des sciences géographiques de l'INCT
Volume 5, Numéro 1, Pages 3-8
2001-04-30

Using Gps And Gravity To Infer Ice Mass Changes In Greenland

Authors : Van Dam Tonie . Larson Kristine . Wahr John . Francis Olivier .

Abstract

Climate research indicates that global warming is occurring and will probably continue to occur for the next several decades. One consequence of a global warming scenario is a global sea level rise that would be expected from 1) the thermal expansion of the near surface ocean water and 2) the melting of the Antarctic and Greenland ice sheets and continental glaciers. Determining the relationship and feedback mechanisms between climate, sea level, and ice mass changes has been difficult because of the lack of appropriate data. It is not even clear, for example, whether changes in the Greenland and Antarctic ice sheets over the last century have caused sea level to rise or have caused it to fall. In this manuscript we describe an ongoing geodetic project to measure changes in the vertical position and surface gravity at bedrock sites along the southern edge of the Greenland ice sheet. The long term goal is to use these measurements to constrain ice mass changes in the southern third of the ice sheet and to eventually contribute useful data to understanding climate variability and its relationship to long-term sea level trends and ice mass changes. We are only 5 years into what we expect to be a decade long set of observations. So we cannot yet comment on present day changes in the ice mass in Greenland. However our measurements to date reveal crustal motions that are substantially larger than anticipated indicating that the ice load history for the Pleistocene ice in Greenland is not well represented in current models.