利用GRACE和地球物理模型研究地球动力学扁率变化
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摘要
作为一个旋转的扁椭球体,地球的动力学扁率J2变化主要是由各圈层相互作用和地球系统的物质流动所引起。当前,测定地球动力学扁率主要是通过卫星激光测距资料获得。本文利用GRACE月重力场模型、海底气压模型和冰期均衡调整模型等估计地球动力学扁率月变化ΔJ2,通过计算得到的C20时间序列与卫星激光测距(SLR)结果差别不大。通过计算分析,可以看出使用不同机构发布的GRACE数据产品,得到的季节变化时间序列的结果差别不大,与SLR结果非常接近,得出的C20时间序列在SLR方差百分比达70%。
As a rotating ellipsoid,the dynamic oblateness( J2) changes of the earth is significantly influenced by the interaction of different layers in the earth system and the redistribution of earth's fluid mass.At present,the dynamic oblateness is usually obtained from the satellite laser ranging( SLR) data. A new method is proposed to estimate changes in the earth's dynamic oblateness,which uses monthly gravity recovery and climate experiment( GRACE) gravity solutions,an ocean bottom pressure model and a glacial isostatic adjustment( GIA) model.The result shows that the time series is similar with the solution based on SLR data.The experiment shows that seasonal variations of the obtained time series are similar with different GRACE data products,which is approximate with the solution based on SLR.
As a rotating ellipsoid,the dynamic oblateness( J2) changes of the earth is significantly influenced by the interaction of different layers in the earth system and the redistribution of earth's fluid mass.At present,the dynamic oblateness is usually obtained from the satellite laser ranging( SLR) data. A new method is proposed to estimate changes in the earth's dynamic oblateness,which uses monthly gravity recovery and climate experiment( GRACE) gravity solutions,an ocean bottom pressure model and a glacial isostatic adjustment( GIA) model.The result shows that the time series is similar with the solution based on SLR data.The experiment shows that seasonal variations of the obtained time series are similar with different GRACE data products,which is approximate with the solution based on SLR.
引文
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[12]PELTIER W.Global Glacial Isostasy and the Surface of the Ice-age Earth:the ICE-5g(VM2)Model and GRACE[J].Annual Review of Earth Planetary Sciences,2004,32(1):111-149.
[13]WAHR J,MOLENAAR M,BRYAN F.Time Variability of the Earth’s Gravity Field:Hydrological and Oceanic Effects and Their Possible Detection Using GRACE[J].Journal of Geophysical Research:Solid Earth,1998,103(B12):30205-30229.
[14]张子占,陆洋,许厚泽.GRACE和SLR观测的地球动力学扁率最大熵谱及小波相关分析[J].地球物理学报,2007,50(5):1383-1389.
[15]曲伟菁,吴斌,周旭华.根据人卫激光测距、GRACE和地球物理模型求解地球低阶重力场季节变化[J].测绘学报,2012,41(6):904-909.
[16]金双根,张兴刚.GPS,OBP和GRACE估计地球动力学扁率变化及其地球物理激发[J].科学通报,2012(36):3484-3492.
[17]曲伟菁.地球低阶重力场变化的研究[D].北京:中国科学院研究生院,2012.
[2]CAZENAVE A,NEREM R S.Redistributing Earth’s Mass[J].Science,2002,297(5582):783-784.
[3]YODER C K,WILLIAMS J G,DICKEY J O,et al.Secular Variations of Earth’s Gravitational Harmonic J2Coefficient from Lageos and Nontidal Acceleration of Earth Rotation[J].Nature,1983,303:757-762.
[4]TAPLEY B D,BATTADPUR S,WATKINS M,et al.The Gravity and Climate Recovery Experiment:Mission Overview and Early Results[J].Geophysical Research Letters,2004,31(9):48-54.
[5]CHEN JL,RODELL M,WILSON CR.Famiglietti JS(2005)Low Degree Spherical Harmonic Influences on Gravity Recovery and Climate Experiment(GRACE)Water Storage Estimates[J].Geophysical Research Letters,2005,32(14):29-37.
[6]CHENG M,TAPLEY B D,RIES J C.Deceleration in the Earth’s Oblateness[J].Journal of Geophysical Research Solid Earth,2013,18(2):740-747.
[7]CHENG M,TAPLEY B D.Variations in the Earth’s Oblateness during the Past 28 Years[J].Journal of Geophysical Research:Solid Earth,2004,109(9):25-36.
[8]BLEWITT G,CLARKE P.Inversion of Earth’s Changing Shape to Weigh Sea Level in Static Equilibrium with Surface Mass Redistribution[J].Journal of Geophysical Research,2003,108(8):2311-2319.
[9]KUSCHE J,SCHRAMA E J O.Surface Mass Redistribution Inversion from Global GPS Deformation and Gravity Recovery and Climate Experiment(GRACE)Gravity Data[J].Journal of Geophysical Research,2005,110(7):2461-2471.
[10]SWENSON S,CHAMBERS D,WAHR J.Estimating Geocenter Variations from a Combination of GRACE and Ocean Model Output[J].Journal of Geophysical Research:Solid Earth,2008:113(B8):2841-2849.
[11]GERUO A,WAHR J,ZHONG S.Computations of the Viscoelastic Response of a 3-d Compressible Earth to Surface Loading[J].Geophysical Journal International,2012,192(2):557-572.
[12]PELTIER W.Global Glacial Isostasy and the Surface of the Ice-age Earth:the ICE-5g(VM2)Model and GRACE[J].Annual Review of Earth Planetary Sciences,2004,32(1):111-149.
[13]WAHR J,MOLENAAR M,BRYAN F.Time Variability of the Earth’s Gravity Field:Hydrological and Oceanic Effects and Their Possible Detection Using GRACE[J].Journal of Geophysical Research:Solid Earth,1998,103(B12):30205-30229.
[14]张子占,陆洋,许厚泽.GRACE和SLR观测的地球动力学扁率最大熵谱及小波相关分析[J].地球物理学报,2007,50(5):1383-1389.
[15]曲伟菁,吴斌,周旭华.根据人卫激光测距、GRACE和地球物理模型求解地球低阶重力场季节变化[J].测绘学报,2012,41(6):904-909.
[16]金双根,张兴刚.GPS,OBP和GRACE估计地球动力学扁率变化及其地球物理激发[J].科学通报,2012(36):3484-3492.
[17]曲伟菁.地球低阶重力场变化的研究[D].北京:中国科学院研究生院,2012.