Comparison of Different Satellite Altimeter-Derived Gravity Anomaly Grids with Ship-Borne Gravity Data Around Australia

Abstract

The GMGA97, KMS01 and Sandwell's v.9.2 grids of marine gravity anomalies, derived from multi-mission satellite altimetry, are compared with one another and with ship-track gravity anomalies computed from the Australian marine gravity database. The results show some significant differences among these data sources, especially close to the coasts and in regions of steep horizontal gravity gradients, such as along the continental shelf. These are attributed to loss of altimeter lock as it passes over the coast and poorly modelled shallow-sea tides, and data interpolation errors, respectively. The comparisons also show that there are some serious biases among ship-tracks in the Australian marine gravity database, which illus-trates that these data have not been crossover cor-rected properly. Therefore, users of any of these data should treat them with caution.