A Study On Methods Of Computing Marine Gravity Field Using Satellite Altimetry Data

It is a very important topic in geodesy and oceanography research to compute marine gravity anomaly using satellite altimetry data. In this dissertation, the researches which are based on the combination of Topex/Poseidon, Jason-1, Jason-2, ERS-2 and Envisat altimetry data are listed as follows:(1)The history of satellite altimetry and its technology is stated detailedly. The applications of satellite altimetry are described briefly as well. Domestic and overseas development of the theory of data processing and computing marine gravity anomaly is also discussed.(2)Based on the satellite altimetry theory, the preprocessing methods, the error sources also with the correctional methods and models are studied. Two methods of computing normal points are analyzed and compared. The sea surface height of the normal points are interpolated using cubic spline function of the first boundary condition. After this, it is converted to grid points using Shepard gridding method.(3)Three methods of computing marine gravity anomaly are studied. The methods of computing marine vertical deflection are studied and compared.(4)The 5? ? 5?grid geoid height of local area is computed. The 5? ? 5?grid vertical deflection of this area is computed using least square collocation method. The 5? ? 5?gravity anomaly is computed using two methods with their precision compared and analyzed.(5)The local gravity anomaly is computed using combined multi-satellite altimetry data. The effect of the sea level rising to the gravity anomaly is analyzed with its correctional model advanced based on its characteristic. The system error is corrected using surface fitting and least square collocation methods. Then the geoid height, vertical deflection and gravity anomaly are recomputed using corrected data with their precision analyzed and compared with those which are computed with data without such corrections.