Bathymetry Inversion And 3D Visualization Based On Gravity Field Data

With the concepts of "Digital Earth " and "Smart Ocean",how to obtain and use seafloor topographic data has become a significant requirement for managing the ocean.High-precision seafloor topography plays an important role in marine research,resource development,military activities and other fields.The traditional method of measuring seabed topography with shipborne sonar is inefficient,time-consuming and laborious,and it is difficult to cover the whole world.Satellite altimetry technology can obtain all day and all-weather ocean observation data,so as to restore the ocean gravity field,and the ocean gravity field information has high correlation with the seabed topography in the relevant band,which makes it possible to retrieve the seabed topography based on satellite altimetry gravity field products.The main work and conclusions of this study are as follows:(1)The inversion formulas of seabed topography based on satellite altimetry gravity anomaly and vertical gravity gradient anomaly data are derived respectively.Taking Mariana Trench and a certain sea area in South China Sea as examples,the 1?x1?seabed topography model in the study area is inversed by frequency domain method based on gravity anomaly and vertical gravity gradient anomaly data.Compared with the shipborne depth data,the results show that both gravity anomaly data and vertical gravity gradient data can retrieve the seabed terrain model with high accuracy;On the whole,the inversion accuracy based on vertical gravity gradient is slightly higher than that based on gravity anomaly.(2)In order to improve the inversion accuracy,this paper further studies the seafloor topography inversion methods based on filter combination strategy and weighted combination strategy.The improvement of the two methods on the bathymetry inversion accuracy are analyzed in the study areas.The results show that: in the Mariana Trench area,the accuracy has no obvious change by fusing the gravity anomaly and gravity gradient inversion results;In the South China Sea,the accuracy of the two combination strategies is higher than that of the inversion using only gravity anomaly or vertical gravity gradient anomaly data,and the accuracy of the inversion results based on the filtering combination strategy is higher than that based on the weighted combination strategy.(3)This paper studies the 3D visualization technology based on Arc Engine and the construction method of DEM based on Irregular Triangulation.On the basis of bathymetry inversion results,3D visualization of seabed terrain is completed based on Arc Engine component in Visual C #.Net development environment.It realizes the function of 3D modeling of seabed terrain,provides human-computer interactive browsing function of 3D terrain such as zoom,navigation and flight,supports regional terrain visualization,3D model import,contour generation and other functions,provides an efficient 3D display platform for large-scale seabed terrain,and lays the foundation for applications of the derived bathymetry.