The geoid of China and its surrounding areas determined by shallow layer method

  • The shallow layer method was introduced
  • China geoid model CGM2021was calculated
  • The comparation between CGM2021 and EGM2008/EIGEN-6C4 geoid in China were given
Abstract

In this study, we established a 5’ × 5’ China geoid model 2021, which is determined based on the shallow layer method (SLM, Shen 2006). We use the external global Earth gravity field models (EGM2008 and EIGEN-6C4), the digital topographic model DTM2006.0 and crust model CRUST1.0 to construct the shallow layer model. The top and bottom boundaries of the shallow layer model are the Earth’s nature surface and a surface below a reference geoid for a certain depth. Then the gravity field in the region inside the shallow layer can be determined. Based on the definition of the geoid W = W0 (where W0 = 62636851.7 m2 s-2 is the geopotential constant on the geoid), we determined the geoid in and around China, which is referred to as CGM2021 (including CGM2021-08 and CGM2021-6C4). Comparisons show that the differences between the CGM2021 and EGM2008 geoid or EIGEN-6C4 geoid in China are in centimeter level in average.

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