Research On Gravity Field Inversion And Multi-source Data Fusion Based On HY-2A Data

Haiyang-2A(HY-2A)is Chinese first dynamic marine environment satellite with marine detection capabilities.Investigations on HY-2A data will have a foundational role in the development of Chinese altimetry satellites in future;the ocean accounts for about 70% of the earth surface.The detection of marine gravity field information is important for environmental,geophysical and earth science research,and can provide a reference for the refinement of global climate models and the exploration of marine resources.This study firstly derives the vertical deflections using HY-2A altimetry satellite data,and then the marine gravity field is further retrieved,which verifies the accuracy of HY-2A observations.In order to improve the accuracy of the derived marine gravity anomalies,the methods of multi-source data fusion are investigated,i.e.,data fusion in frequency domain and data fusion using wavelet analysis.The differences between the fusion results and the standard model are derived and analyzed.Compared with the “pure” HY-2A derived results,the accuracy of fusion results is higher.The data processing and fusion methods used in this paper can provide a basis for the subsequent research on the HY-2B and HY-2C altimetry satellite data.The main research work and conclusions are as follows:(1)The HY-2A satellite altimetry data is preprocessed,the error items are corrected,and the vertical deflections and ocean gravity anomaly of a part area in the western Pacific are derived.The results show that the accuracy of the east-west component of the vertical deflections is lower than that of the north-south component,and the accuracy of the ocean gravity anomaly is better than 7.5m Gal.(2)On the basis of the HY-2A satellite altimetry gravity anomaly data,the study further use the shipborne gravity anomaly data and the GRACE satellite gravity anomaly data to fuse the three types of data in the frequency domain;The results show that the accuracy of the fused gravity anomaly is improved by 1.36 m Gal.(3)The wavelet analysis method is used to analyze the HY-2A gravity anomaly,shipborne gravity anomaly,and gravity satellite data in four layers,and the above-mentioned data is fused through wavelet inverse transformation,and the accuracy of the fusion is improved by 1.01 m Gal.