COMPARISON OF GOCE DERIVED SATELLITE GLOBAL GRAVITY MODELS WITH EGM2008, THE OCTAS GEOID AND TERRESTRIAL GRAVITY DATA: CASE STUDY FOR NORWAY

摘要

Global gravity models composed of a set of spherical harmonic coefficients represent one of the most important products of the GOCE satellite gradiometry mission. These are of particular interest in many geoscientific disciplines dealing with the Earth’s gravity field. At present, four satellite-only global gravity models based on GOCE observations have been made available to the scientific community. Three of them have been determined by independent strategies using pure GOCE satellite-to-satellite tracking and satellite gravity gradiometry observations. The fourth model has been computed from a combination of GRACE and GOCE observations. In this contribution, GOCE derived global gravity models are compared with EGM2008, the OCTAS geoid and terrestrial gravity anomalies. We restrict our numerical study to the territory bounding the continental part of Norway. Spherical harmonic expansions have been truncated at maximum degree and order 200 corresponding to a spatial resolution of 100km. Higher frequencies contained in the OCTAS geoid and in the terrestrial gravity anomalies have been removed by explicitly applying a low-pass filter on the data sets, or by removing the signal content of EGM2008 above degree 200.