Influence Analysis of High-order Seafloor Topography on Sea Surface Gravity Information

  Objectives   In order to make the best use of seafloor topographic information contained in gravity data and improve the quality of seafloor topographic inversion results based on gravity data, the South China Sea is selected as the experimental sea area.

  Methods   The effects of different order seafloor in frequency domain are discussed in detail when recovering the gravity anomaly and vertical gravity gradient anomaly in different seafloor topographic environments.

  Results   The results of numerical analysis and experiment show that the results of one-time seafloor topographic play a major role in the contribution of gravity information. With the increase of the order of seafloor topography, the amplitude of gravity information decreases continuously. The high order gravity anomaly/vertical gravity gradient anomaly varies obviously in the sea area where the seafloor topography fluctuates sharply and its amplitude is larger, while gravity information varies slightly in the flat sea area. The vertical gravity gradient anomaly is more sensitive to high frequency part of seafloor topography than gravity anomaly.

  Conclusions   In the process of inversion of seafloor topography based on gravity data, if the input data source is gravity anomaly, it is suggested that the second term of seafloor topography should be taken into account. If the input data source is vertical gravity gradient anomaly, it is suggested that the third term or the fourth term of seafloor topography should be taken into account so as to make full use of the information contained in gravity data.