摘要
喀喇昆仑山叶尔羌河冰川突发洪水在1987年暴发之后沉寂了近10a,但最近10a(1997—2006年)突发洪水又频繁发生.2002年8月13日发生的冰川湖突发洪水,下游卡群站洪峰流量达4670m3·s-1,洪量125×106m3,远超过1987年实测上游冰湖最大蓄水量.利用多景Landsat 7 ETM+影像对该次洪水进行了研究分析,在克勒青河谷的影像上发现了长6.02km,面积3.01km2的冰川阻塞湖.利用2002年8月最大冰川湖的数据结合实测地形图,估算出冰坝较1987年实测值升高了约35m.分析周边气候资料认为,近20a夏季气温下降和冬季降水增加导致流域内冰川前进,冰川湖规模扩大,是叶尔羌河冰川洪水频率和幅度增加的主要原因.
Glacier dammed lakes play a prominent role in the landscape-shaping processes in the Karakoram Mountains. Glacier lake outburst floods （GLOFs） have been a source of many local and some regional disasters and cause serious hazard. Hydrological records at the downstream gauging station on the Yarkant River in the Karakoram Mountains show that GLOFs now frequently repeat from the glacier lakes 500 km upstream, after an inactive phase of 10 years （1987-1996）. In this paper, an abnormal GLOF and a glacier-dammed lake are described and analyzed using Landsat7 ETM＋ imagery in 2002. The GLOF was observed at the downstream station in August, 2002, of which the maximum peak discharge and water volume were of 4 670 m^3 · s^-1 and 125 × 10^6 m^3, respectively. The former was four times larger than the meltwater flood rate, and the latter exceeded the potential capacity of glacier lake surveyed in 1987. Analyzing the Landsat7 ETM＋ imagery, it is found that the dammed lake is clearly visible along the Shaksgam valley at 4 700 m to 4 860 m in summer, with a maximum length of 6.02 km and an area of 3.01 km^2. It is believed that the GLOFs frequently occurrence caused by glacier advances at the lake basins results from the ice dam rise. It is estimated that the dam rose about 35 meters as compared with that in 1987. In the recent decades, a decrease in both summer air temperature and meltwater and an increase in winter precipitation due to the increasing Indian Monsoon resulted in glacier advancing, glacier lake expanding, which also cause GLOFs occurrence more frequent and more intensive.
出处
《冰川冻土》
CSCD
北大核心
2009年第5期808-814,共7页
Journal of Glaciology and Geocryology
基金
国家重点基础研究发展计划(973计划)项目(2007CB411503)
中国科学院重大方向项目(KZCX2-YW-310)
科技部攻关项目(2006FY110200)
中国科学院""百人计划"项目资助
