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由于可以探测到视线向的微小形变量,重复轨道雷达干涉测量(INSAR)成为探测极地冰流的有效手段。基于ERS-1/2SAR影像的INSAR已经成功获取了南北极许多地区的冰流信息。采用最新的ENVISAT ASAR影像,利用干涉方法获得了东南极内陆格罗夫山地区的首幅ASAR干涉条纹图(其中包括地形信息和冰流信息)。其与利用该地区1996年ERS-1和JERS-1数据所获得的干涉条纹进行对比表明,在格罗夫山角峰群内分布有两个冰流子系统,且状态较为稳定,ENVISAT ASAR数据在冰盖干涉测量方面具有良好的性能和应用潜力。
The ability of detecting small look-of-sight deformation remotely and precisely makes repeat-pass SAR interferometry an effective means for detecting ice flow over polar ice sheet.INSAR measurements based on ERS-1/2 SAR images have revealed various ice motions on ice sheet in Arctic and Antarctica.The latest and advanced SAR sensor is the ASAR sensor carried on-board the ENVISAT satellite launched in early 2002.Few interferometric applications of ASAR are reported till present,even fewer on glacier motion study in Antarctica.Grove Mountain is the newly found meteorites trap in East Antarctica.The wide-spread nunataks makes the ice flow quite complex in this region,which makes the ice motion measurement challenging.In this paper,a 35-day-apart ENVISAT ASAR image pair acquired at the end of 2004 is selected for interferometry to calculate the interferogram in Grove Mountain.The resulting interferogram consists of both topography and ice flow information.For evaluation,the interferograms of the same region calculated from sequential ERS-1 and JERS-1 image pairs acquired in 1996 were introduced for analysis.As for the difference of L and C band radar in sensitivity to displacement,the fringe densities of JERS and ASAR interferogram are different while the patterns are similar.The shape and distribution of ERS and ASAR interferometric fringes are slightly different for the difference in sensitivity to displacement in near and far range of SAR imagery.The qualitative comparisons indicate that ENVISAT ASAR data is of fine quality in such application on INSAR over ice sheet.The quantitative analysis shows that the motion state of revealed two ice flow subsystems among nunataks in Grove Mountain are relatively stable.Further research will focus on the topography removal,noise reduction and quantitative analysis of the composite interferogram.