利用动力学方法解算GRACE时变重力场研究  

An investigation on GRACE temporal gravity field recovery using the dynamic approach

作　　者：王长青[1,2] 许厚泽[1] 钟敏[1] 冯伟[1] 冉将军[1] 杨帆[3] 

机构地区：[1]中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室,武汉430077 [2]中国科学院大学,北京100049 [3]华中科技大学物理学院,武汉430074

出　　处：《地球物理学报》2015年第3期756-766,共11页Chinese Journal of Geophysics

基　　金：国家重大科学研究计划(2013CB733305;2012CB957703);国家自然科学基金(41174066;41131067);大地测量与地球动力学国家重点实验室项目(L2013-6)联合资助

摘　　要：本文利用动力学方法建立GRACE（Gravity Recovery And Climate Experiment）K波段距离变率（KBRR）观测、轨道观测与重力场系数的观测方程,通过GRACE Level 1B观测数据,成功解算出全球月时变重力场模型——IGG时变重力场模型,并将2008—2009年的解算结果与GRACE三大数据处理机构美国德克萨斯大学空间中心CSR（Center for Space Research）、美国宇航局喷气推进实验室JPL（Jet Propulsion Laboratory）和德国地学研究中心GFZ（GeoForschungs Zentrum）发布的最新全球时变重力场模型进行详细对比分析.结果表明：IGG结果在全球质量异常、中国及周边地区质量异常的趋势变化、全球质量异常均方差、2~60每阶位系数差值以及亚马逊流域和撒哈拉沙漠等典型区域平均质量异常等方面与CSR、JPL和GFZ解算的RL05结果较为一致.其中,IGG解算结果在2~20阶与CSR、GFZ和JPL最新解算结果基本一致,20~40阶IGG解算结果与GFZ、JPL单位最新解算结果较为接近,大于40阶IGG结果介于CSR与GFZ、JPL之间;亚马逊流域平均质量异常周年振幅IGG、CSR、GFZ和JPL获取到的结果分别为17.6±1.1cm、18.9±1.2cm、17.8±0.9cm和18.9±1.0cm等效水柱高.利用撒哈拉沙漠地区的平均质量异常做反演精度评定,IGG、CSR、GFZ和JPL的时变重力场获取到的平均质量异常均方差分别为1.1cm、0.9cm、0.8cm和1.2cm,表明IGG解算结果与CSR、GFZ和JPL最新发布的RL05结果在同一精度水平.The Gravity Recovery and Climate Experiment（GRACE）mission can significantly improve our knowledge of the temporal variability of the Earth′s gravity field.We intend to obtain monthly gravity field solutions based on dynamic approach（variational equations approach）from GPS-derived positions of GRACE satellites and K-band range-rate measurements.Moreover,these solutions will validate through GRACE RL05 products published monthlygravity field solutions by the GRACE project,which including CSR（Center for Space Research）,JPL（Jet Propulsion Laboratory）and GFZ（GeoForschungsZentrum）.Based on the theory of the dynamic approach,the processing began with the computation of purely dynamic orbits by fitting GNV1 Borbits computed by the GRACE team using a reduced dynamic strategy.This step aimed to calibrate the GRACE A and B accelerometer data and the initial state vectors of these two satellites.Note that gravity field model parameters were not adjusted in this part.In the next step,the purely dynamic orbits were used as the reference orbit for the calculation of residual orbits,and were also applied to calculate the nominal value of Kband range-rate.In addition,the partial derivatives with respect to the initial state vectors,accelerometer parameters and geopentional coefficients were computed simultaneously with the integration of the purely dynamic orbits.Finally,normal equations of orbit positions and K-band range-rate measurements were synthesized using a fixed data weighting ratio to combine the both information matrices for the best combined solution.The monthly gravity field solution obtained though above procedures was named as the IGG temporal gravity field model.IGG temporal gravity field models were compared with GRACE RL05 products in following aspects：（i）monthly gravity field solutions in February,2008 and September,2009;（ii）the root mean squares of the global mass anomaly during 2008 to 2009;（iii）the trend of the mass anomaly in China and its nearby regions within 2008 to 20

关 键 词：GRACE 时变重力场 动力学方法 等效水柱高 

分 类 号：P223[天文地球—大地测量学与测量工程]