东喀喇昆仑山昆常冰川近期跃动特征  

Characteristics of recent surging of Kunchhang Glacier,East Karakoram

作　　者：杨婧睿 蒋宗立[1] 刘时银 王欣[1] 张勇[1] 张震 魏俊锋[1] YANG Jingrui;JIANG Zongli;LIU Shiyin;WANG Xin;ZHANG Yong;ZHANG Zhen;WEI Junfeng(Hunan Provincial Key Laboratory of Geo-Information Engineering in Surveying,Mapping and Remote Sensing,Hunan University of Science and Technology,Xiangtan 411201,Hunan,China;Institute of International Rivers and Eco-security,Yunnan University,Kunming 650500,China;School of Geomatics,Anhui University of Science and Technology,Huainan 232001,Anhui,China)

机构地区：[1]湖南科技大学测绘遥感信息工程湖南省重点实验室,湖南湘潭411201 [2]云南大学国际河流与生态安全研究院,云南昆明650500 [3]安徽理工大学测绘学院,安徽淮南232001

出　　处：《冰川冻土》2021年第6期1732-1745,共14页Journal of Glaciology and Geocryology

基　　金：国家重点研发计划项目(2018YFE0100100);国家自然科学基金国际合作项目(41761144075);国家自然科学基金项目(41471067)资助。

摘　　要：研究冰川跃动过程及特征是理解冰川跃动机理的重要途径,目前仍然缺乏详细的冰川跃动过程观测。利用Envisat-1/ASAR、Sentinel-1A、TerraSAR-X/TanDEM-X等合成孔径雷达数据,获得了东喀喇昆仑山昆常冰川详细的表面流速与表面高程变化。结果表明:2000—2012年冰川中部隆起,平均增厚(10.19±1.79)m,冰川接收区以消融为主,平均减薄(39.71±1.79)m;2012—2014年冰川主干中部隆起向下迁移,平均增厚(8.21±1.37)m;2018年后积蓄区厚度平均减薄(9.77±3.38)m,接收区平均增厚(19.67±3.38)m。冰川主干表面流速从2007年起增加,并且在2017—2018年内经历过两次快速运动期,两个阶段的最高流速分别达到2.36m·d^(-1)和2.12m·d^(-1)。根据表面高程变化以及流速变化特征,认为昆常冰川在2007—2019年间发生跃动。时序流速表明,昆常冰川很可能是积蓄区发生微跃动/雪崩形成隆起(跃动前锋),并且两次快速运动后突然减速发生在夏末,很可能是冰下水文通道打开排水使得冰下静水压力减弱从而导致跃动停止,属于阿拉斯加型跃动。结合ITS_LIVE流速数据分析,初步确定其近两次跃动的间隔约为30年。同时对比时间序列的Landsat图像发现,2004—2005年间昆常冰川南分支发生跃动,致使分支末端的小冰湖消失。The process and characteristics of glacier surging are important to understand glacier surging mechanism.In this paper,the velocity and surface elevation of Kunchhang Glacier,East Karakoram are obtained and analyzed by using Envisat-1/ASAR,Sentinel-1A,TerraSAR-X/TanDEM-X datasets.The results show that from 2000 to 2012,the average thickness increasing of the central glacier upstream was(10.19±1.79)m,and the glacier receiving area was mainly melting,with an average thinning of(39.71±1.79)m;from 2012 to 2014,the formed bulge moved downward,with an average thickness increasing of(8.21±1.37)m;combined with ICESat-2 laser altimetry data in 2018 and 2020,it is found that the overall thickness of reservoir area decreased by(9.77±3.38)m,and the average thickness of central trunk(receiving area)was(19.67±3.38)m.Surface velocity of the trunk of glacier has increased significantly since 2007,and has experienced two rapid flow periods during 2017—2018,and the maximum velocity of the two stages reaches 2.36 m·d^(-1) and 2.12 m·d^(-1),respectively.According to change of elevation and characteristics of flow velocity,we consider that Kunchhang Glacier experienced surging from 2007 to 2019.The time series of velocity shows that Kunchhang Glacier was likely to be formed by mini-surge/avalanche in the reservoir area(surge front),and the two rapid movements suddenly decelerated at the end of summer.It is likely that the opening of the subglacial hydrological channel reduced the hydrostatic pressure under the ice,leading to the surge terminate,which belongs to the Alaskantype.According to the analysis of ITS_LIVE velocity data,the period of the surge is about 30 years.Comparing with the Landsat images of time series,it is found that the southern branch of Kunchhang Glacier experienced surging from 2004 to 2005,resulting in the disappearance of the small glacial lake between the terminus and the glacier trunk.

关 键 词：冰川跃动 冰川表面流速 TerraSAR-X/TanDEM-X ICESat-2/ATLAS 东喀喇昆仑山 

分 类 号：P343.6[天文地球—水文科学]