Calculation of geoid undulations and gravity anomalies in the Northwest Pacific by using the Topex/Poseidon and Geosat altimeter data

The geoid undulations in the Northwest Pacific were calculated by using the Topex/Paseidon and Geoeat altirreter data.Firstly the bias between two types of the altimeter data was removed and the geoid undulations in the Northwest Pacific were acquired by a long wave bias diminishing model with a resolution of 30 km and precision of 14 cm.Then an algorithm of inversion of gravity artarrtalies was derived,and the gravity anomalies in the East China Seawere calculated by using the algorithm and the geoid undulationts.The rms of difference between the in situ measurements and the gravity anomalies from altimeter data was 3.8×10^-5 m/s².A method to calculate the gravity artornalies in a larger area was developed which combined gravity anomalies in four subregions overlapping each other into one data set in a larger region.The error analysys shows that the model and result of the inversion of gravity anomalies were reliable.