High spatio-temporal resolution changes in Earth's gravity field from GOCE with application to ice mass balance

In late 2007, the European Space Agency's first Earth Explorer mission will be launched. The Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission, is focused on the determination of a high resolution and accuracy (~1cm at 116km) global static gravity field and its subsequent exploitation to determine the steady-state dynamic ocean topography. It is scheduled to operate for two six month observation windows each separated by approximately 6 months. Mission extension may allow further observation windows. While the focus of GOCE data is on the static gravity field it will be sensitive to mass variations over each six month window. The proposed research is to implement an algorithm to allow for time-variable gravity fields to be determined ahead of the GOCE data release. Namely, over each 6 month observation window, we will determine a secular change in the gravity field. The purpose of this is to, in the future, exploit the GOCE data in this way to enable a greater understanding of rapid ice mass changes observed notably in SE Greenland and parts of Antarctica.