Earth's Gravity Field Derived from Grace Satellite Tracking Data

Abstract

An Earth's gravity field model IGGGRACE01S has been derived from 141 days of GRACE tracking data, including K-band, accelerometer, and satellite orbit data. The model resolves the geoid with an accuracy of about 0.012m at a resolution of 500m half-wavelengths, it improves the accuracy of the gravity field model in the long- to medium-wavelength part (< 80 degree) in comparison with the pre-CHAMP model. Comparing the coefficients of IGGGRACE01S, EIGEN-GRACE02S, EIGEN-CHAMP03S and EGM96 models, the result shows that the coefficients of IGGGRACE01S are much closer to those of EIGEN-GRACE02S, and very different to those of the other two models. Comparing the geoid undulations and gravity anomalies derived from IGGGRACE01S, EIGEN-GRACE02S and EGM96 models, the results indicate that the IGGGRACE01S solution is much closer to EIGENGRACE02S solution, and there exist large differences between IGGGRACE01S and EGM96 in Antarctica region. Comparing the gravity anomalies derived from IGGGRACE01S (72 degree) with NIMA gravity anomalies data (2.5° × 2.5°), the standard deviation is 4.8 mGal in China mainland region.