Earth＇s gravity model（EGM） helps people better determine the figure of Earth, which is generally represented by a global geoid. For a considerable amount of practical applications, people use quasi-geoid to approxi...Earth＇s gravity model（EGM） helps people better determine the figure of Earth, which is generally represented by a global geoid. For a considerable amount of practical applications, people use quasi-geoid to approximate the geoid, thus the quasi-geoid is also treated as an important height datum. In this study we revisit the method to directly determine regional quasi-geoid using EGM and digital elevation model（DEM）, on the basis of Molodensky theory. According to the method we obtain a 50 50quasi-geoid for China's Mainland and its vicinity areas, based on the EGM2008 gravitational potential model and the Shuttle Radar Topography Mission（SRTM） DEM model. By comparing height anomalies derived from EGM2008 with observations at 70 GPS/leveling points in areas including northwest,mid-west, mid-east and southeast of China, we find that the 50 50EGM2008 quasi-geoid well fits the GPS/leveling results, with average deviations less than 10 cm for the selected areas in east China（with mainly plain topography） and ~20 cm for the selected areas in west China（highland or mountainous areas）. We also discuss a few technical issues for directly determining height anomalies based on EGM and DEM, under the frame of Molodensky theory.展开更多
基金supported by the National 973 Project of China(2013CB733301)the Natural Science Foundation of China(41204017,11173049,41429401 and 41228004)+1 种基金the Shanghai Postdoctoral Sustentation Fund(13R21417900)the Special Program Fund of Shanghai Astronomical Observatory(Y196591009)
文摘Earth＇s gravity model（EGM） helps people better determine the figure of Earth, which is generally represented by a global geoid. For a considerable amount of practical applications, people use quasi-geoid to approximate the geoid, thus the quasi-geoid is also treated as an important height datum. In this study we revisit the method to directly determine regional quasi-geoid using EGM and digital elevation model（DEM）, on the basis of Molodensky theory. According to the method we obtain a 50 50quasi-geoid for China's Mainland and its vicinity areas, based on the EGM2008 gravitational potential model and the Shuttle Radar Topography Mission（SRTM） DEM model. By comparing height anomalies derived from EGM2008 with observations at 70 GPS/leveling points in areas including northwest,mid-west, mid-east and southeast of China, we find that the 50 50EGM2008 quasi-geoid well fits the GPS/leveling results, with average deviations less than 10 cm for the selected areas in east China（with mainly plain topography） and ~20 cm for the selected areas in west China（highland or mountainous areas）. We also discuss a few technical issues for directly determining height anomalies based on EGM and DEM, under the frame of Molodensky theory.
