Refining Local Earth's Gravity in Spatial Domain with Residual Terrain Modelling Technique

  Objectives  The land high-resolution gravity data is the basis of the research on ultra-high-degree gravity field model and its application.But the existing observation technology and means limit the coverage area of land gravity measurement, and there are still a lot of areas without gravity measurement.

  Methods  Based on the residual terrain modelling method, short-wave signal of 3″×3″ resolution shuttle radar topography mission(SRTM) V4.1 data is extracted using high-pass filtering technology, combined with the EGM2008 gravity field model, to inverse and refine local gravity field parameters with 1'×1' resolution. 57 387 points of NGS99 are used to test the local gravity field of America with 1'×1' resolution restored by this method. Then this method is applied to the North China Plain (114°E—117°E, 32°N—35°N), and gravity disturbance and vertical deflection of 1'×1' resolution in this area are calculated.

  Results  Compared with EGM2008 model, the root mean square(RMS) of error is reduced from 15.470 mGal to 12.999 mGal. In the North China Plain, the RMS of gravity disturbance is 25.311 mGal, and the RMS of South-North and East-West vertical deflections are 2.215″ and 8.452″, respectively.

  Conclusions  This method can effectively improve the resolution of the land gravity field while ensuring the accuracy, and fill in the blank of 1'×1' resolution ground gravity measurement.