Global derivation of marine gravity anomalies from Seasat, Geosat, ERS-1 and TOPEX/Poseidon altimeter data

Marine gravity anomalies over the area 82°S, to 82°N and 0°E to 360°E on a 2′ × 2′ grid have been derived from Seasat, Geosat, ERS-1 and TOPEX/Poseidon altimeter data. The inverse Vening Meinesz formula with a 1-D FFT method was used to compute gravity anomalies from gridded north-south and west-east geoid gradients, in a remove-restore procedure with the EGM96 gravity model as the reference field. This paper presents a new gridding technique and an altimeter data management system that help to extract data efficiently in the 12 areas where ship-measured gravity and satellite-derived gravity were compared, rms agreements of 5-14 mgal were obtained. Special discussions of the gravity anomalies over selected inland seas, the Arctic, Antarctica and coastal waters are presented. The derived gravity anomalies show detailed tectonic structures of the world ocean. The global data set will be continuously updated with more altimeter data included in the derivation.