中文摘要：

2002年发射的GRACE重力卫星为南极冰盖质量平衡提供了一种新的测量方式,但由于南极GIA模型的不确定较大,进而影响GRACE结果的可靠性.本文联合2003—2009年的GRACE和ICESat等数据实现了南极GIA信号的分离,联合方法所分离的GIA不依赖于不确定性很大的冰负荷等假设模型,而是直接基于卫星观测数据估算而来的,具有更大的可靠性.在分离过程中,本文提出了冰流速度加权改正法和GPS球谐拟合改正法对GIA结果进行精化,同时引入了南极GPS观测站的位移数据对分离的GIA进行详细的评估和验证,GPS验证表明经过冰流速度加权和GPS球谐拟合双改正后的GIA结果精度明显得到提高.最后本文利用所分离的GIA对GRACE和ICESat结果进行了改正,得到2003—2009年南极冰盖质量变化的趋势为-66.7±54.5 Gt/a（GRACE）和-77.2±21.5Gt/a（ICESat）,相比采用其他的GIA模型,本文的GIA结果使GRACE和ICESat这两种不同观测技术得到的南极冰盖质量变化结果更加趋于一致.

英文摘要：

The Antarctic Ice Sheet（AIS）is the largest single mass of ice on Earth,if fully melted,would contribute more than 60 meters of sea level rise.Accurate quantification of the mass balance of AIS is very important to improve our understanding and prediction of its response and contribution to sea level change.The Gravity Recovery and Climate Experiment（GRACE）mission has provided a new means to detect AIS mass change since its launch in 2002,but thereare large uncertainties in applying GRACE to estimate AIS mass balance.Of these,the dominant error comes from the inaccurate knowledge of Glacial Isostatic Adjustment（GIA）,which is the ongoing response of the solid Earth due to the changing ice-ocean load during the last ice age.The fact that GRACE senses all sources of mass change at the Earth′s surface requires removing non-glacier changes by independent datasets or models.Mass change signals associated with GIA are poorly known in Antarctica due to very sparse geophysical and climatological data to constrain the glacial history and often dominate GRACE error budgets.In this study,we explore an approach to estimate GIA through the combination of GRACE satellite gravity and Ice,Cloud,and Land Elevation Satellite（ICESat）altimetry data sets.The GIA results are completely independent of any previous reconstruction of the Antarctic glacial history and derived from direct observations by satellite techniques.Our study developed the approach proposed by Gunter et al.（2014）for empirical estimation of present-day Antarctic GIA and ice mass change using a combination of satellite altimetry and gravimetry.An ICESat surface height change estimated from the crossover analysis approach was combined with three different GRACE solutions for the period between February of 2003 and October of 2009.Based on the previous method of the low-precipitation zone（LPZ）bias correction,weighted ice flow speed correction and GPS spherical fitting methods are created.When the GIA results computed by the combination data wer