supported by the National 973 Project of China(2013CB733301);the Natural Science Foundation of China(41204017,11173049,41429401 and 41228004);the Shanghai Postdoctoral Sustentation Fund(13R21417900);the Special Program Fund of Shanghai Astronomical Observatory(Y196591009)
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...