Evaluation of Recent GRACE and GOCE Satellite Gravity Models and Combined Models Using GPS/Leveling and Gravity Data in China

A total of 649 GPS/Leveling points and 799897 2' x 2' gridded mean gravity anomalies in mainland China are used for the evaluation of the recently released Earth Gravitational Models (EGMs) including the GOCE only models (GO_CONS_GCF_2_TIM_R3 (GO_TIM_R3), GRACE only models ITG-Grace2010s, combined satellite gravity field models (GO_CONS_GCF_2_DIR_R3 (GO_DIR_R3), GOCO03S, DGM-1S, EIGEN-5S, EIGEN-6S), and combined gravity field models (EIGEN-51C, EIGEN-6C, GIF48, EGM2008) from satellite observations and ground gravity data sets. The statistical results show that in mainland China the most precise model is EIGEN-6C with the standard deviation (STD) +/-0.183 m of the quasi-geoid height differences compared with the GPS/Leveling data and the STD +/-22.5 mGal of the gravity anomaly differences compared with the gridded mean gravity anomalies from observations. For EGM2008, they are +/-0.240 m and +/-24.0 mGal respectively. Among the satellite only gravity models from GRACE, GOCE and LAGEOS observations, GO_TIM_R3 is the best one in mainland China, and the STDs of the corresponding quasi-geoid differences and the gravity anomaly differences are +/-0.459 m and +/-31.3 mGal respectively, which are nearly at the same levels as the ones for the models EIGEN-6S, GOCO03S and GO_DIR_R3. This shows that the GOCE mission can recover more medium-short wavelength gravity signals in mainland China than former satellite gravity missions.