GRACE重力卫星探测南极冰盖质量平衡及其不确定性  

Ice sheet mass balance in Antarctica measured by GRACE and its uncertainty

作　　者：高春春[1,2] 陆洋[1] 张子占[1,3] 史红岭[1,4,5] 朱传东[1,2] 

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]美国德克萨斯大学空间研究中心,奥斯汀78759 [4]极地测绘科学国家测绘局重点实验室,武汉430079 [5]地理空间信息工程国家测绘地理信息局重点实验室,北京100830

出　　处：《地球物理学报》2015年第3期780-792,共13页Chinese Journal of Geophysics

基　　金：国家重点基础研究发展计划(973计划)(2013CB733301,2012CB957703);国家自然科学基金(41274025,41174064,41021003,40904020);极地测绘科学国家测绘地理信息局重点实验室开放基金(201204);地理空间信息工程国家测绘地理信息局重点实验室资助项目(201307);国家海洋局极地科学重点实验室开放研究基金(KP201202);大地测量与地球动力学国家重点实验室自主项目(SKLGED2013-2-2-Z);中国科学院测量与地球物理研究所重要方向项目(Y309451048)联合资助

摘　　要：2002年GRACE重力卫星的成功发射为南极冰盖质量平衡的研究提供了重力探测的新纪元.本文利用美国德克萨斯大学CSR公布的2003年1月到2013年12月期间的RL05版本GRACE月重力场数据,采用最优平均核函数法和组合滤波法两种GRACE后处理方法反演了南极冰盖质量的时空变化.结果表明:在2003—2013年期间南极冰盖物质平衡呈明显的负增长状态,质量变化趋势为-163±50Gt/a(GW13)、-129±41Gt/a(IJ05)、-81±27Gt/a(W12a),加速度为-8±10Gt/a2,质量消融的主要区域分布在西南极阿蒙森海岸和南极半岛的北部.另外本文还重点探讨了可能影响到估算结果的各项误差及不确定性,分析结果显示影响南极冰盖质量平衡估算结果的最大误差源为GIA改正.通过假设检验和信息准则对时间序列分析中拟合参数的合理选取进行了探讨和分析,在联合周年项、半年项和S2、K2、K1潮汐混频项进行拟合分析时发现K1项对拟合结果的加速度影响比其他周期项稍大,尽管考虑该项的合理性因当前GRACE数据时间序列长度有限而无法确切证实,但K1项的影响值得后续关注.对比两种GRACE后处理方法的结果发现:当采用的数据时间跨度一致,误差改正方法相同,两种相异的后处理方法,其估算结果也具有较好的一致性.As a critical component of the cryosphere,the Antarctic Ice Sheet（AIS）has strongconnection with the sea level change and global climate change.Accurate quantification of the current spatial and temporal mass changes of AIS is very important to improve our understanding and prediction of its response and contribution to global change.The Gravity Recovery and Climate Experiment（GRACE）mission has provided new and useful observations to detect AIS mass balance since its launch in March 2002.There are significant differences among the GRACE estimates of the total mass change.The big difference is due in part to considerable uncertainty in the accuracy of glacial isostatic adjustment（GIA）signals,and also due to use of different time spans,different versions of GRACE products and different GRACE post-processing methods.Using 124 monthly GRACE gravity field solutions of Release 5（RL05）produced at the Center for Space Research（CSR）of the University of Texas,Austin,spanning the interval from January of 2003 through December of 2013,the mass balance of AIS is estimated by two postprocessing ways：the optimizing averaging kernel method（also named VW）and the combined filter method（the first step is called P5M11 decorrelation filter to remove correlated noise by fitting and subtracting a fifth-order polynomial to even and odd coefficient pairs at spherical harmonic orders eleven and above,the second involves smoothing with a 250 km Gaussian filter）.A detailed error analysis is provided including consideration of leakage-in,leakage-out,and errors in modeling mass variations of the atmosphere,ocean and GIA.In addition,a statistical model selection criterion is employed in computation of trends from mass variation time series,and the impact of K1 tidal alias is analyzed.The results reveal that during 2003—2013,the total mass of the ice sheet decreased significantly at change rates of-163±50,-129±41and-81±27Gt/a for three GIA models：GW13,IJ05,W12 a.There was a distinct region with mass loss in t

关 键 词：南极冰盖 质量平衡 GRACE 不确定性 后处理方法 

分 类 号：P312[天文地球—固体地球物理学]