用GRACE卫星跟踪数据反演地球重力场

利用141天GRACE卫星观测资料，包括K波段、星载加速度和卫星轨道数据，反演了80阶地球重力场模型IGGGRACE01S，该模型在半波长为500km的空间分辨率上，确定大地水准面的精度约为0012m，中长波(<80阶)精度优于重力卫星发射以前研制的重力场模型. 与EIGEN_GRACE02S、EIGEN_CHAMP03S和EGM96模型的位系数相比，该模型系数最接近于EIGEN_GRACE02S，与另两个模型差异较大. 比较几种模型确定的全球重力异常和大地水准面起伏，结果发现IGGGRACE01S与EIGEN_GRACE02S模型的计算结果比较接近，与EGM96模型结果差异较大，差别较大地区主要在南极等地区. 对于中国大陆，比较IGGGRACE01S模型（前72阶）计算的重力异常和NIMA重力异常数据（25°×25°网格），两者之间的标准偏差为48mGal.

Earth's gravity field derived from GRACE satellite tracking data

An Earth’s gravity field model IGGGRACE01S has been derived from 141 days of GRACE tracking data, including K_band, accelerometer, satellite orbit data. The model resolves the geoid with an accuracy of about 0012m at a resolution of 500km half_wavelength, it improves the accuracy of the gravity field model in the long_ to medium_wavelength part (<80 degree) than pre_CHAMP model. Comparing the coefficients of IGGGRACE01S, EIGEN_GRACE02S, EIGEN_CHAMP03S, and EGM96 models, the result shows that the coefficients of IGGGRACE01S are close to those of EIGEN_GRACE02S, and much different to those of the other two models. Comparing the geoid undulations and gravity anomalies derived from the above_mentioned models, the results indicate that the IGGGRACE01S solution is close to EIGEN_GRACE02S 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 land region.