Estimations of glacier melting in Greenland from combined satellite gravimetry and icesat

摘要

The Gravity Recovery and Climate Experiment (GRACE) and the Ice, Cloud, and land Elevation Satellite (ICESat) missions can estimate the ice mass changes in Greenland. The GRACE monthly time-varying gravity filed solution can be used to infer the redistribution of temporal redistribution with a limited spatial resolution of 300-500 km, while the ICESat measurements can estimate the elevation variations of ice-sheet with high-precision but have a limited temporal coverage and the assumption of snow/ice density when used to monitor the mass change of Greenland ice sheet. The combination of these two independent measurements will overcome each shortcoming, improving not only the resolution capability but also the reliability of estimated results of ice mass changes. In this paper, glacier variations in Greenland are investigated by joint GRACE and ICESat measurements. The ice mass change rate in Greenland is - 142.14 Gt/yr, and the acceleration is -16.28 Gt/yr2 from GRACE during January 2003 to June 2007, while the total ice mass loss is at 173.03Gt/yr at the same period from ICESat measurements. The combined estimation of Greenland ice sheet loss rate is -157.59 Gt/yr fromGRACE and ICESat with more smooth and high resolution.