摘要
跃动冰川作为一种特殊类型的冰川,蕴含着巨大的灾害风险,对其开展监测研究具有重要意义。本研究基于1973年以来的Landsat影像、ASTER立体像对和ITS_LIVE数据产品,监测分析了帕米尔中部North Kyzkurgan冰川在跃动前、跃动中、跃动后的面积、高程、流速变化,揭示了该冰川完整的跃动发生过程。结果表明:North Kyzkurgan冰川是一条典型的跃动冰川,在1973—2011年处于恢复阶;2011—2016年处于跃动阶;2016年之后重新进入恢复阶。North Kyzkurgan冰川所在地区气候寒冷,降雪量丰富,同时该冰川积累区面积比率超过0.8,冰川作用正差近1000 m,因此冰川补给物质充足。在积蓄区物质积累、不断增厚的情况下,冰川底部达到压力熔点,融水不断增多,在融水的润滑和顶托作用下,最终导致冰川发生跃动。因此,North Kyzkurgan冰川跃动的发生主要与热力学因素有关。
As a special type of glacier,surging glaciers are often related to glacier hazard events such as glacial lake outburst flood,glacial debris flow and landslide.Although only 1%of the world’s glaciers have been ob⁃served to surge,the scientific and practical significance of surging glaciers can not be ignored.In this paper,based on Landsat MSS/TM/ETM+/OLI images,ASTER stereo pair images,and ITS_LIVE data,we obtained the glacier area,elevation and velocity changes of the North Kyzkurgan Glacier in central Pamir before,during and after the surging,and revealed the complete surge process of this glacier.The results show that,the North Kyzkurgan Glacier is a typical surging glacier,which was in the quench phase during 1973—2011,in the active phase during 2011—2016.After 2016,the glacier entered a quench phase again.In the active phase of 2011—2016,the glacier terminal rapidly speeds up and advances,with marked thinning over the accumulation area and thickening on the ablation area.The active phase of the surging glacier was 6 years,the quench phase was likely about 40 years at least.The main reason behind the glacier surge may be the extremely low temperature and abundant precipitation,as was recorded at the Fedchenko Meteorological Station in 1935—1990.In addition,the accumulation area ratio of the North Kyzkurgan Glacier is more than 0.8,and the positive difference of glaci⁃ation is about 1000 m,so the glacier material accumulation is rapidly.With the continuous thickening of glacier accumulation area which build-up by snowfall,avalanches and drifting snow,the glacier bed was raised to the pressure melting point and produced meltwater.The meltwater reduced basal drag and faster sliding,and finally led to the glacier surging.Therefore,the surging of the North Kyzkurgan Glacier was mainly caused by thermal⁃ly mechanism.
作者
李志杰
王宁练
侯姗姗
LI Zhijie;WANG Ninglian;HOU Shanshan(Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity,Xi’an 710127,China;Institute of Earth Surface System and Hazards,College of Urban and Environmental Sciences,Northwest University,Xi’an 710127,China;CAS Center for Excellence in Tibetan Plateau Earth Sciences,Beijing 100101,China)
出处
《冰川冻土》
CSCD
北大核心
2021年第5期1267-1276,共10页
Journal of Glaciology and Geocryology
基金
中国科学院战略性先导科技专项(XDA19070302,XDA20060201)
第二次青藏高原综合科学考察研究项目(2019QZ⁃KK020102)资助。
