Abstract We introduce an iterative inversion method to address the problems in high-order seafloor topography inversion using gravity data (gravity anomaly and vertical gravity gradient anomaly), such as the difficulty in computing the equation and the uniqueness of the calculation results. A part of the South China Sea is selected as the experimental area. Considering the coherence and admittance function of gravity topography and vertical gravity gradient topography, the inversion band of the gravity anomaly and vertical gravity gradient anomaly in the study area is 30 km–120 km. Seafloor topography models of different orders are constructed using an iterative method, and the performance of each seafloor topography model is analyzed against ETOPO1 and other seafloor topography models. The experimental results show that as the inversion order increases, the clarity and richness of seafloor topographic expression continuously improve. However, the accuracy of seafloor topography inversion does not improve significantly when the inversion order exceeds a certain value, which is related to the contribution of high-order seafloor topography to gravity information. The results show that the accuracy of BGT4 (inversion model constructed by the gravity anomaly) is slightly poorer than that of BVGGT4 (inversion model constructed by the vertical gravity gradient anomaly) in areas with complex topography, such as multi-seamounts and trenches, and the results are generally better in areas with flat seafloor topography.

中文翻译：

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应用迭代法求解海底地形高阶项

摘要 针对重力数据（重力异常和垂直重力梯度异常）在高阶海底地形反演中存在方程计算困难、计算结果唯一性等问题，引入迭代反演方法。选择南海的一部分作为试验区。考虑重力地形与垂直重力梯度地形的相干导纳作用，研究区重力异常与垂直重力梯度异常的反演带为30km～120km。使用迭代方法构建不同阶次的海底地形模型，并针对ETOPO1和其他海底地形模型分析每个海底地形模型的性能。实验结果表明，随着反演阶次的增加，海底地形表达的清晰度和丰富度不断提高。然而，当反演阶数超过一定值时，海底地形反演的精度并没有显着提高，这与高阶海底地形对重力信息的贡献有关。结果表明，在多海山、海沟等复杂地形地区，BGT4（重力异常构造反演模型）精度略低于BVGGT4（重力垂直梯度异常反演模型）精度；在海底地形平坦的地区，结果通常更好。当反演阶次超过一定值时，海底地形反演精度没有明显提高，这与海底地形高阶对重力信息的贡献有关。结果表明，在多海山、海沟等复杂地形地区，BGT4（重力异常构造反演模型）精度略低于BVGGT4（重力垂直梯度异常反演模型）精度；在海底地形平坦的地区，结果通常更好。当反演阶次超过一定值时，海底地形反演精度没有明显提高，这与海底地形高阶对重力信息的贡献有关。结果表明，在多海山、海沟等复杂地形地区，BGT4（重力异常构造反演模型）精度略低于BVGGT4（重力垂直梯度异常反演模型）精度；在海底地形平坦的地区，结果通常更好。