利用新型C波段雷达卫星研究南伊内里切克冰川运动特征

利用新型C波段Sentinel-1卫星获取的2015年2月至2017年2月期间的影像数据，研究分析了天山中部南伊内里切克冰川不同时段的运动特征。利用偏移量追踪技术计算不同时间段冰川位移，首先采用三步配准的方法进行主辅影像高精度整体配准，然后基于归一化互相关（normalized cross correlation，NCC）算法通过调整窗口参数精确估算局部偏移量，进一步分离得到冰川移动信息。监测结果表明:（1）在空间分布上，狭长的冰舌区是冰川主要的高速流动区域，冰舌区底部流速小于上部，两侧流速小于中间，末端流速明显减缓。（2）在季节变化上，冰川运动速率与温度变化趋势一致，在5月至8月期间运动速率最快，沿剖面线的最高速率达49 cm/d；在11月至次年2月期间运动最为缓慢，速率为25~30 cm/d左右。（3）在年度变化上，2015年夏季的运动速率比2016年整体高约1~3 cm/d，其他季节则没有明显差异。与高分辨率L波段PALSAR-2影像的监测结果进行定量对比分析时，将冰舌区的像元进行抽稀后统计，得到两种数据获取的运动速率之差的均值为3.48 cm/d，标准差为±3.78 cm/d，证实了南伊内里切克冰川运动监测结果的可靠性。

Motion Characteristics of the South Inilchek Glacier Derived from New C-Band SAR Satellite

This study present the results of measuring the motion characteristics of the South Inilchek glacier with the C-band Sentinel-1 images acquired from February 2015 to February. 2017. During the offsets estimation in offset-tracking method, we firstly adopt three-step method to achieve high precision overall registration, and then change the matched window size to estimate the local offset with the NCC(normalized cross correlation) algorithm, which was further separated to get glacier motion information. The observation results show that the significant high-speed flow area was the ice tongue, where the flow velocity reduced from the upper to the bottom and slowed obviously at the end, and increased from its both sides to the middle. Moreover, the glacier motion velocity had the same trend with the temperature variation seasonally. The glacier tongue moved with the maximum average velocity of 49 cm/d during the period of May to August, and with the slowest moving in the interval from November to February for about 25-30 cm/d. While in terms of annual changes the velocity in the summer of 2015 was higher than that in 2016 as a whole for about 1-3 cm/d, and there was no marked difference in the other seasons. Furthermore, the monitoring result was demonstrated by comparing the results from Sentinel-1 images in quantity with that from high resolution L-band PALSAR-2 images. The statistics of the sparse pixels in the tongue indicated that the average of the velocity difference was 3.48 cm/d and the standard deviation was ±3.78 cm/d, which confirmed the reliability of the results.