A Fast Method for Calculation of Marine Gravity Anomaly

Yuan Fang,Shuiyuan He,Yongkang Gan,Xiaohong Meng,Jun Wang,Hanhan Tang

doi:10.3390/app11031265

Abstract

Gravity data have been playing an important role in marine exploration and research. However, obtaining gravity data over an extensive marine area is expensive and inefficient. In reality, marine gravity anomalies are usually calculated from satellite altimetry data. Over the years, numerous methods have been presented for achieving this purpose, most of which are time-consuming due to the integral calculation over a global region and the singularity problem. This paper proposes a fast method for the calculation of marine gravity anomalies. The proposed method introduces a novel scheme to solve the singularity problem and implements the parallel technique based on a graphics processing unit (GPU) for fast calculation. The details for the implementation of the proposed method are described, and it is tested using the geoid height undulation from the Earth Gravitational Model 2008 (EGM2008). The accuracy of the presented method is evaluated by comparing it with marine shipboard gravity data. Its efficiency is demonstrated through comparison with the conventional sequential method. The tests demonstrate that the proposed method can be employed for accurately calculating marine gravity anomalies and provides an advantage on computational efficiency.

Highlights

With the gradual deepening of global exploration, the ocean, which covers about 70% of the Earth [1], has become a key study area for future resource detection [2]
The geoid height undulation data, which were used in these tests, were all obtained from the Earth Gravitational Model 2008 (EGM2008) model
The geoid height undulation data of the EGM2008 model can be calculated from the file geoidegm2008grid.mat, which can be found on the official website of MATLAB (Appendix A)

Summary

Introduction

With the gradual deepening of global exploration, the ocean, which covers about 70% of the Earth [1], has become a key study area for future resource detection [2]. After decades of development, resolving gravity anomalies from the satellite altimetry data has gradually become the mainstream approach for obtaining marine gravity anomalies [3,4,5,6] For this method, the satellite altimetry data are processed to obtain the sea surface height [3,7,8]. The sizes of the covariance matrices are related to the numbers of the predicted marine gravity anomalies and the given geoid height undulation. For the calculation of large-scale marine gravity anomalies, the LSC generates large covariance matrices, which leads to the problem of large matrix inversion. The LSC method is time-consuming when calculating large-scale marine gravity anomalies. The judgment statements should be used to solve the singularity problem in the calculation, which further increases the computing time

Methods

Results

Conclusion