GOCE observations in exploration geophysics

The satellite GOCE has produced an extraordinary global gravity field with a spatial resolution of 80 km at a precision of 1-2 mGal. When considering geologic structures, the wavelengths of interest for exploration purposes are smaller. We show that the GOCE data produce a new quality assessment tool for fields of higher resolution, which all necessarily rely on terrestrial data. The space-borne control of terrestrial data is necessary in order to obtain 100% reliability of existing data or to assess the quality of newly acquired data. We propose a scheme for controlling and testing the quality of higher resolution data, for example airborne campaigns or the EGM08 global gravity field. EGM08 has the higher resolution of 10 km, but with varying quality, depending on the terrestrial data availability. We show how the quality assessment can be made using the GOCE data, giving confidence in the successive modelling results. Specifically we consider the African continent. Africa is an example where terrestrial data area scarce and where the reliability of EGM08 is very variable, jeopardizing the usefulness of the field if the quality assessment with the GOCE da is not fulfilled.