Recovery Of Local Offshore Marine Gravity Field With Satellite Altimetry Data

The satellite altimetry is a new spatial measuring technology Developed in 1970s, as computer technology and space technology has developed.Satellite altimetry is carried by satellite,measuring the global sea surface height,using spatial,electronic and microwave technology.Satellite altimetry can provide distance between the ocean surface to the center of the earth repeatedly and accurately in all-weatherly in the global extent.It creates a new technology for the research on sea surface changes.We can get geoid,sea surface topography,gravity anomalies,and so on from satellite altimetry data;provide an important gist for navigation,oceanography,geophysics.In the introduction,a brief account of the status of satellite altimetry,and the development of satellite altimetry are introduced,as well as its important applications.In chapter 2,it is devoted to describe the basic principles of satellite altimetry,the error sources,error model,and satellite-related surfaces:the reference ellipsoid,geoid, mean sea level,sea surface topography,and so on.The third chapter is the theoretical part of this paper.Several ways of how to get marine geoid by using altimetry data are introduced in this part.Inverse operation of deviations of the vertical is explained detailedly in this part,because it's used in the experiment.Chapter 4 is the experimental part of this paper.Experimental data,plan of experimental,experimental steps,results and analysis of the experiment are introduced in this part.Three methods are tried to improve the inversion accuracy of marine gravity field:choose a suitable radius of the points,enlarge radius of Integral step by step,and the terrain correction method.The conclusions and outlooks are given in chapter 5.The main research achievements are as follows:1.Stationary sea surface topography(SST) focuses on long-wave.In the Inverse Vening-Meinesz formula,a larger Integral radius will bring long-wave errs;a smaller Integral radius could reduce long-wave error from SST,and improve the accuracy of the Gravity.In this paper,satellite altimetry data are used calculated marine gravity. And the conclusion is that 30'-60' is the most suitable Integral radius.2.Since the geoid is focuses on long-wave,a larger Integral radius should be better.But In the Inverse Vening-Meinesz formula,a larger Integral radius will bring long-wave errs.Enlarger the integral radius step by step has been proved to be effective in the experiment to improve the accuracy of the Gravity.3.Terrain correction can be used to smooth gravity field,and to keep consonance of the gravity field.There are land and islands in calculation region.Terrain correction can improve the accuracy of this part of land and islands.However,Terrain correction of sea water can not smooth the sea area gravity field,can't be used to improve the accuracy of gravity field.