Determination Of Marine Gravity Anomalies And Geoid By Using Satelliate Altimetry Data

The emergence of satellite altimetry has provided with the sea surface height datawhich constitutes the2/3of the world. Satellite altimetry can provide the observationsof sea surface height not only in daily and repeat cycles,but also in high accuracy, whichensure the stable quantity of data for marine gravity field,ocean dynamics and so on.Theusing of multi-satellite altimetry data has been a certain trend in the determination ofmarine gravity field,so how to derive marine gravity field by using multi-satellitealtimetry data becomes the crucial problem,which also is the topic of research for thisdissertation.In this dissertation, the main work and achievements are as follows:1. In the dissertation, the edit criteria and geophysical corrections of every satelliteare discussed in detail, and a good pre-process criterion is concluded.2. The deflection of the vertical has computed by using the position and timeinformation of cross-over points in China sea and its adjacent seas,its validity andcredibility was obtained by comparing with EGM2008.EGM2008was used as referencefiled,and the resiual deflection of the vertical gridded in2′×2′was acquried byprocessing with the remove-restore technique and continuous curvature splineinterpolation in tension.3. Based on the resiual deflection of the vertical,the gravity anomalies gridded in2′×2′in China sea and its adjacent seas were derived by using the inverse VeningMeinesz formula and the fast Foutier transform technique.In the process,the innermostzone effect was considered and the gravity anomalies of the gravity field model wasrestored.Compared with the shipboard gravimetry,the accuracy of derived gravityanomalies is±8mgal in South sea with complex terrain,however, it is±5.3mgal in Eastsea with relatively flat terrain.4. The geoidal undulation gridded in2′×2′in China sea and its adjacent seas wasdetermined by using the deflection of the vertical and gravity anomalies.The results bymaking use of the two different methods were compared and its rms was±2.8cm.It showsthat the accuracy is good.