中文摘要：

介绍了利用GRACE卫星数据计算和分析重力场变化的方法。以EIGEN—GRACE02S重力场模型为背景，对高斯平滑处理前后中国大陆月重力场的变化作了比较，认为取平均半径为666km作高斯平滑，能够得到合理的重力变化结果。以3个月时间尺度计算了2008年汶川地震前后中国大陆的重力场变化，将结果与2006年和2007年相同时间尺度的变化结果进行比较，发现三者相符合，并且同震重力的负变化可用地壳膨胀模型理论来解释。

英文摘要：

The method of calculating and analyzing the variation of gravity field with the GRACE satellite data is intro- duced. Taking the EIGEN-GRACE02S as a reference, we compare the monthly variation of the gravity field in Chinese mainland before the Gaussian Smoothing with the one after the Gaussian Smoothing. The reasonable vari- ation of the gravity field can be obtained by Gaussian Smoothing when taking 666 km as the average radius. We calculate the variation of gravity field in Chinese mainland before and after the Wenchuan Ms8.0 earthquake in 2008. By three-month scale we compare the gravity field with the ones in 2006 and in 2007 and find that the three variation in three different years are accordant with each other. The negative coseismic gravity changes can be in- terpreted by the expansion of the Earth＇s crust model.