新疆克拉牙依拉克冰川变化(1973—2016)主被动遥感监测分析

Karayaylak glacier changes in the Kongur Mountain of eastern Pamir between 1973 and 2016 based on active and passive remote sensing technologies

2015年5月,新疆克拉牙依拉克冰川西支发生跃动,本文利用1973年美国锁眼(Key Hole)卫星光学遥感数据、2000年的美国SRTM DEM数据以及2013年、2016年的TanDEM-X双站InSAR数据,获取了1973—2016年克拉牙依拉克冰川的表面高程变化情况。结果表明,1973—2013年,克拉牙依拉克冰川积累区出现轻微高程减薄,2013—2016年,西支冰川末端表面高程增厚明显,冰川上部则出现清晰的表面高程减薄;利用2013—2016年Landsat ETM+光学遥感数据监测了冰川表面运动速度变化,发现西支冰川从2015年4月中开始活动强烈,到跃动发生时,运动速度到达顶峰。综合分析认为,跃动发生前该冰川末端未出现明显前进或者后退的趋势,而冰川流速发生了较大的变化;此外,结合气象站点数据结果,认为该冰川此次跃动与局部气候变化关系不大,跃动的主要原因很可能为冰川自身结构变化,为本区域冰川灾害预警机制的建立提供了数据基础。

Located on the northern slope of Kongur Mountains,Karayaylak glacier surged in May 2015.For the purpose of obtaining the glacier surface elevation changes of the Karayaylak glacier from 1973 to 2016,the authors used the 1973 Keyhole satellite optical remote sensing data,the US SRTM DEM data in 2000,and the TanDEM-X bistatic SAR data in 2013 and 2016.The results show that,from 1973 to 2013,there was no obvious elevation change;from 2013 to 2016,clear surface thickening was observed at the terminus of the west branch,whereas a relatively obvious glacial surface elevation thinning was detected in the upper part of the glacier.Landsat OLI image from 2013 to 2015 were employed to monitor the change of glacier surface velocities.The distributions and changes of the glacier surface velocities indicate that the western tributary of Karayaylak glacier moved faster than any other tributaries.According to the comprehensive analysis,it is considered that there is no obvious advance or retreat trend at the terminus of the glacier before glacier surge,and the flow velocity of the glacier has changed greatly.In addition,combined with the results of meteorological data,it is believed that the glacial surge has little to do with local climate change.The main reason for the surge is probably attributed to the structural change of the glacier itself.