Norwegian validation and exploitation of GOCE gravity data

The Nordic countries constitute a key study region for Earth system sciences. The climate is strongly depending on ocean currents in the North Atlantic. A detailed description of the currents is a key to a better understanding of regional and global clima te mechanisms. A crucial quantity for related investigations is detailed knowledge of the marine geoid, the horizontal surface at mean sea level, from which the time averaged ocean surface deviates due to steady-state ocean circulation. On March, 17 this year, ESA launched its first Earth Explorer Core Mission, the highly sophisticated dedicated gravity satellite GOCE. The mission will deliver homogeneous information on the static geoid with unprecedented accuracy and spatial resolution. The main applicat ion is expected in oceanography and in solid Earth physics. The GOCE satellite carries the first gravity gradiometer ever flown in space. A crucial point in the use of such a new technology is the calibration and validation of the measurements. This is al so a prerequisite for the necessary combination of GOCE and terrestrial data. The current proposal aims at the external validation of GOCE data by comparison with independent terrestrial gravity in Norway. ESA will provide an official global gravity fiel d model to the international user community. As such this model will be optimal on a global scale. Therefore the proposal also aims at a regional gravity field recovery from GOCE data, optimally tied to the Nordic area and specifically oriented towards op timal combination with all available terrestrial data (including ship and airborne gravity). This way the Norwegian University of Life Sciences intends to take full advantage of GOCE for applications in and around Norway. The international scientific part ners contribute with their expertise in mathematical modelling of the local and regional geoid structures as well as with detailed insight in the whole GOCE data processing chain.