Contributions of GRM to the ocean topography experiment (TOPEX)

The permanent shape of the sea surface, the time averaged mean sea level, is comprised of: (1) an ellipsoidal component due to the mean mass of a rotating Earth; (2) spatial undulations due to the inhomogeneous distribution of mass in the Earth; and (3) spatial undulations due to permanent ocean currents. The amplitude of the three components are in the ratio 10,000 : 100 : 1 m, the first two components comprising the marine geoid, and the third being the permanent topography of the sea surface.