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合成孔径雷达(SAR)因其可全天时、全天候工作且不受云、雨的影响而成为遥感应用的前沿领域。SAR干涉测量(Inteferometry)利用SAR数据的相位信息可获得大地表面厘米级的形变而成为冰川表面流速监测广泛使用的手段;SAR图像相关方法(SRFT)能克服干涉测量方法因失相干严重而难以产生清晰的干涉条纹以及可见光图像质量由于云遮、雪盖限制的不足而成为目前山地冰川表面流速遥感监测的首选方式。为深入探讨SAR图像相关方法的适用性,以天山科契卡尔巴西冰川为研究区域,分析使用不同时间基线的ALOS PALSAR数据与ENVISat ASAR C-band的图像相关方法估计冰川的表面流速,并使用实地测杆的DGPS(Differential GPS)测量流速进行对比验证,发现在冰川表碛覆盖区域使用图像相关方法测量的值与实测值有很好的一致性,而在裸露冰区域或坡度较大区域,误差比较大。比较长时间基线的SAR数据对特征识别的结果发现:时间基线为1a的冬季获取的数据对估计值与实测值在表碛覆盖区域比较一致,这可能是由于前后两次获取图像时天气或地面状况比较接近。比较ALOS PALSAR数据与ENVISat ASAR数据发现:波长较长的L-band(23.5cm)比C-band(5.7cm)SAR数据更适合山地冰川的表面流速估计;另外在运用SAR数据特征匹配方法时也可能是极化方式的差异使得ALOS PALSAR(HH极化)数据比ENVISat ASAR(VV极化)数据更适合冰川研究。
Synthetic aperture radar (SAR) is the forefront of remote sensing applications because it can work all day, all weather and without being affected by clouds and rain. SAR interferometry uses the phase information of the SAR data to obtain centimeter-scale deformation of the earth’s surface and becomes a widely used means for monitoring glacier surface velocities. The SAR image correlation method (SRFT) can overcome the serious problem of interferometry due to the loss of coherence Clear interference fringes and visible light image quality are the preferred method of remote monitoring of surface glacier surface velocities due to cloud cover and snow cover limitations. In order to further explore the applicability of the SAR image correlation method, the glacier’s surface velocity is estimated using the image-related method of ALOS PALSAR data and ENVISat ASAR C-band at different time baselines for the study area of the Kicar Glacier in the Tianshan Mountains. It is found that there is a good agreement between the measured data and the measured data by using the image correlation method in the covered area of the glacier moraine. In the bare ice area or in the area with large gradient, the error bigger. Comparison of long-term baseline SAR data with feature recognition revealed that the data obtained in winter with a baseline of 1 a were consistent with the observed and observed values in the moraine-covered region, possibly due to the two weather acquisitions or ground acquisition The situation is relatively close. Comparing the ALOS PALSAR data with the ENVISat ASAR data found that longer wavelength L-band (23.5 cm) is more suitable for surface glacier than the C-band (5.7 cm) SAR data; in addition, when applying SAR data feature matching method Possibly polarization differences make ALOS PALSAR data more suitable for glacier research than ENVISat ASAR (VV polarization) data.