Determination of the height of Mount Everest using the shallow layer method

Abstract

Shallow layer method (SLM) based on the definition of the geoid can determine the gravity field inside the shallow layer. In this study, the orthometric height of Mount Everest (HME) is calculated based on SLM, in which the key is to construct the shallow layer model. The top and bottom boundaries of the shallow layer model are the natural surface of the Earth and the surface at a certain depth below the reference geoid, respectively. The model-combined strategies to determine the geoid undulation (N) based on SLM are applied to calculate the HME by two approaches: (1) direct calculation by combining N and geodetic height (h); (2) calculation by the segment summation approach (SSA) using the gravity field inside the shallow layer. On December 8, 2020, the Chinese and Nepalese governments announced an authoritative value of 8848.86 m, which is referred to a geoid determined by the International Height Reference System (IHRS) (i.e., the geopotential is 62636853.4 m2s-2). Here, our results (combined strategies (1) EGM2008 and CRUST1.0, (2) EGM2008 and CRUST2.0, (3) EIGEN-6C4 and CRUST1.0, and (4) EIGEN-6C4 and CRUST2.0) are referred to the geoid defined by WGS84 (i.e., the geopotential is 62636851.7 m2s-2). The differences between our results and the authoritative value (8848.86 m) are 0.448 m, −0.009 m, −0.295 m, and −0.741 m by the first approach, and 0.539 m, 0.083 m, −0.214 m, and −0.647 m by the second approach. When the reference surface WGS84 geoid is converted to the IHRS geoid, the differences are 0.620 m, 0.163 m, −0.123 m, and −0.569 m by the first approach, and 0.711 m, 0.225 m, −0.042 m, and −0.475 m by the second approach.

Keywords

• Mount everest
• Orthometric height
• Shallow layer method
• Gravity field
• Crust model