Abstract
In this paper we present the concepts and realization of the shallow-layer Shen geoid determination method, which is quite different from the classical geoid modeling methods (Stokes' method, Molodenskii's method, etc.), for determining the global or regional geoids. This method takes full advantage of the precise Earth gravity field model EGM2008, digital topographic model DTM2006.0 and global crust model CRUST2.0 of a shallow layer, a layer from the Earth's surface to a depth. As a case study this method is applied to the determination of a 5' × 5' geoid over the Xinjiang and Tibetan regions, which ranges from latitude 25 to 50°N and longitude 70 to 100°E. The modeled 5' × 5' regional geoid is compared with the EGM2008 geoid model in the same study area and validated by 21 GPS/leveling benchmarks (GPSBMs) distributed sparsely in the Xinjiang area. The results show that the regional geoid reaches an accuracy of ~18 cm and agrees with the GPSBMs better than the EGM2008 geoid in the Xinjiang region.
Highlights
The geoid, defined as the equipotential surface that best approximates the mean sea level, is the most natural representation of the Earth’s figure and is used as vertical datum in many countries
This paper describes the Shen (2006) concept, method, data and computational strategies used to determine the geoid of the Xinjiang and Tibetan region and provides comparison and validation results with the EGM2008 geoid and GPS/leveling benchmarks in this region
A 5 ́ × 5 ́ topography of this area is shown in Fig. 4, where the mesh was computed based on DTM2006.0 to degree and order 2160
Summary
The geoid, defined as the equipotential surface that best approximates the mean sea level, is the most natural representation of the Earth’s figure and is used as vertical datum in many countries. Two classical geoid modeling methods, Stokes’ method (e.g., Stokes 1849) and Molodenskiĭ’s method (e.g., Molodenskiĭ 1962), are used via the corresponding boundary-value problem solutions, namely, the Stokes boundary-value problem and the Molodenskiĭ boundary-value problem (e.g., Hofmann-Wellenhof and Moritz 2005). The former leads to the geoid solution, the latter to the quasi-geoid. This paper describes the Shen (2006) concept, method, data and computational strategies used to determine the geoid of the Xinjiang and Tibetan region and provides comparison and validation results with the EGM2008 geoid and GPS/leveling benchmarks in this region.
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