Methodology Research Of Bathymetry Inversion Based On Multi-satellites Altimeter Data

The seafloor relief is the data basic of marine geology,marine geophysics and marine geodesy,it is significant in ocean research.The traditional method of submarine topography is measured by shipborne sonar.Usually it is inefficient and the coverage can not be met.Satellite altimetry can observe all time and all weather,a wide range and high precision sea surface height data can be acquired.The inversion of gravity anomaly can be calculated by mathematic model,then the inversion of relief model can be computed by the correlation with gravity anomaly and submarine topography.Several principles and methods of bathymetry inversion based on gravity anomaly was stated in this paper.The South China Sea submarine topography was computed by SAS method and gravity geologic method based on HY-2 and other altimeter data,and result was compared and analyzed.The main achievements are as follows:(1)With HY-2 and other multi-satellites altimeter data,data edit and preprocessing was beginning in the research area,including error correction,collinear and crossover adjustment.Data quality and precision was improved after preprocessing,providing guarantee for the inversion of gravity anomaly and seafloor relief.(2)Taking the South China Sea as research object,gravity anomaly with 1?×1?resolution was computed by using sea surface height data after preprocessing based on the principle of deflection of vertical method.The RMS of the difference between the inversion gravity anomaly and shipboren gravity anomaly was 4.5 mgal.It indicated that the precision of inversion gravity anomaly was high.(3)Based on the inversion of gravity anomaly,the South China Sea relief model with1?×1?resolution was computed by SAS method and gravity geologic method respectively,combined with shipborne bathymetric data and submarine topography model.The SAS method was used to inverse bathymetry,the scale factor with residual gravity and residual bathymetry was 10.32 m/mgal.The gravity geologic method was used to compute bathymetry,the best density difference constant via iterative method was 1.32g?cm~3.The RMS of SAS model and GGM model difference was 180m and 115m respectively,compared with shipborne bathymetric data.The precision of SAS model and GGM model are higher than ETOPO1 model and DTU10BAT model.