The Verification of GOCE Geoid Models Using GPS/Leveling in Taiwan

• Main Authors: Huang, Jing-Yao, 黃敬堯
• Other Authors: Cheng, Kai-Chien
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/42779950320948700049

碩士 === 國立中正大學 === 應用地球物理研究所 === 101 === The GOCE (Gravity field and steady-state Ocean Circulation Explorer) Mission of the European Space Agency (ESA) is currently the only one using the satellite gravity gradiometry (SGG) technique for exploring the Earth¡¦s gravity. The satellite-observed gravity data is combined to the surface gravity measurements (on land, airborne or shipborne) in order to form a precise model with high-spatial resolution. One of the goals of the GOCE Mission is to provide 1-cm accuracy geoid with the spatial resolution of about 100 km. Hence, we attempted to verify the geoid model derived from GOCE and other gravity missions, such as GRACE (Gravity Recovery and Climate Experiment), CHAMP (CHAllenging Minisatellite Payload), EGM2008 (Earth Gravitational Model 2008), and a local geoid model with the geoid undulation observed at about 2,000 benchmarks in Taiwan by GPS leveling. The objective of this study is to analyze the models and find the best one that one could work with in GPS leveling work in Taiwan. We have categorized the entire Taiwan island into 5 different regions based on their geological settings in order to test the models. The result indicates the local geoid model released by the Ministry of the Interior, the so-called Hwang’s model, is the best choice due to its consistent datum with GPS and the inclusion of very dense surface, shipborne and airborne gravity measurements. The discrepancy of Hwang’s model to the GPS leveling is around 5-10 cm, whereas that of EGM2008 is around 30 cm, that of GOCE is 30-100 cm.