We analyze the effect of approximate velocity in the formula of the rotation of the gravitational potential. The effect of the rotation of the gravitational potential is caused by the Earth rotation. The difference between the satellite ephemeris's velocity and numerical integral's velocity is computed. The ephemeris data come from GFZ's Rapid Science Orbit, TUM's Reduced-Dynamic Orbit, GFZ's Post-processed Science Orbit respectively. The integral data are obtained from reference gravity field model EGM96, EIGEN2, EIGEN-CG01C respectively. The fitting between ephemeris velocity and integral velocity from EIGEN2 reference gravity field model is better than that from EGM96 and EIGEN-CG01C model. The variations of velocity difference show obvious periodicity, which coincides with the satellite orbit period. When 1m 2 /s 2 for the disturbing potential, or 2mm/s for the approximate velocity in the formula of the rotation of the gravitational potential is required, only the satellite orbit data not satisfying the potential rotation computing demand need to be rejected in GFZ's Rapid Science Orbit and TUM's Reduced-Dynamic Orbit. If the disturbing potential 0.5m 2 /s 2 is desired at satellite track, the satellite velocity required by the formula of the rotation of the gravitational potential should be re-computed or GFZ's Post-processed Science Orbit is adopted.

In combination with the topography model EGM96 for stationary sea surface, we use high‐precision grid data of sea surface anomaly from satellite altimeter measurements in ten years to construct the time series for the formation of the sea surface topography in the South China Sea and calculate the circulation fields of its upper layer in different periods. Comparison between the satellite tracing observations to drifting buoys and the geostrophic current fields in corresponding times indicates that the circulation fields derived by this study can reveal some characteristics of the circulation and eddy over the South China Sea on medium‐ and small‐scales. Based on the circulation field structure of the uppermost layer of the South China Sea averaged to seasons of many years, we make a preliminary analysis of the annual and seasonal variations of the circulation in the study area. The result shows that the circulation of the uppermost layer of the South China Sea is always in a constant process of change and evolution which exhibits pronounced multi‐scale characteristics both in time and space.