Accuracy of Regional Geoid Modelling with GOCE

摘要

Regional geoid models are based on the combination of satellite-only gravity field information and terrestrial data. Satellite information is conveniently provided in terms of spherical harmonic global potential models. Terrestrial information is mostly provided in terms of point or block mean values of gravity in the region of interest. Combination of the two sources of information in the overlapping spectral band is either based on deterministic or on stochastic considerations. We have tested different schemas for weighting satellite and terrestrial information and compared the results to GNSS-levelling data in Norway. The results provide implications for the quality of terrestrial data in the study area and for regional geoid modeling based on GOCE satellite models in general. In order to minimize the computational burden, we avoid field transformation (from gravity anomalies to geoid heights) by employing an already existing regional geoid model to represent the terrestrial information. Combination is then performed by filtering geoid grids in the spatial domain.