利用2009-05~2010-12共20mon的GRACE时变重力场反演了山西省境内陆地水储量变化造成的地表垂直位移,并与同期的GPS高程残差进行了比较。结果显示,对大部分CORS站而言,GRACE反演的水文地壳垂向形变与GPS高程残差时间序变化量均在-6~6mm之间;由二者提取的年周期信号平均振幅均为2.5mm左右,但是相位存在较大差异。由于GPS数据处理过程未考虑周日、半周日大气潮汐,高阶电离层,及非潮汐海潮的影响,这三项误差会传播到测站坐标的时间序列,对GPS周年信号产生影响,所以可以认为GRACE与GPS结果的差异更多的是来自GPS数据处理的误差。
Hydrological processes cause variation in gravitational potential and surface de- formations,both of which are detectable using space geodetic techniques. We computed sur- face vertical displacements due to inland water storage changes using GRACE time-variable gravity field for GORS sites in Shanxi province, during from May 2009 to Dec. 2010, and compared the results with GPS height residuals during the same period. The results demon- strate that variations of hydrological surface deformation derived from GRACE and GPS height residual time series, for most CORS sites, are both about +6.0 ram. The average am- plitudes of annual signal extracted from GRACE and GPS are both about 2.5 ram, however, the phase discrepency is large. Since no corrections were applied for diurnal and semi-diurnal atmospheric loading, high order ionosphere, and non-tidal ocean loading, which would prop- agate into site coordinates time series and affect GPS annual signals. Therefor, we believe that the disagreement between GRACE and GPS is more due to errors in the GPS data pro- cesslng