帕隆藏布江上游冰湖分布及其变化

Distribution and Change of Glacier Lakes in the Upper Palongzangbu River

利用高分辨率遥感影像的判读,结合现场调查、校核和前人资料分析,研究了西藏自治区帕隆藏布江上游然乌—培龙段冰湖的分布变化规律。结果发现:(1)该区有大小冰湖131个,其中面积>0.01km2的有99个,最大冰湖面积达到0.976km2。(2)99个面积>0.01km2的冰湖中冰碛湖最多达68个,占68.7%;分布于海拔4 500～5 000m的冰湖有53个,占53.3%。(3)可对比的83个冰湖中,冰碛湖总面积2005年为7.21km2,较1988年的7.03km2仅增加2.56%。其中,面积减小的有45个,占54.2%,面积增加的38个,占45.8%。(4)近18a来,该冰湖区总面积变化很小,但部分冰湖面积增大异常,受海洋性冰川影响,在该区域内出现大范围冰湖溃决的可能性很小,但暴发零星冰湖溃决的可能性很大。

Combined with field investigations and historical data,interpretation of high-precision remote sensing images shows the following facts about glacier lakes within the Ranwu—Peilong section in the upper Palongzangbu River.（1） There were 131 glacier lakes of various sizes totally,of which 99 were larger than 0.01 km2,with the largest being 0.976 km2.（2） 68 out of the 99 glacier lakes were morained lakes,with 53 distributing between 4 500 and 5 000 m altitude and accounting for 68.7%.（3） The total area of the 83 comparable glacier lakes increased by only 2.56%,from 7.03 km2 in 1998 to 7.26 km2 in 2005.（4） The total area of glacier lakes varied little in the last 18 years,but some had an abnormal increase in area.These glacier lakes are all oceanic,so the lakes are unlikely to break at a large scale and only occasional outburst is possible.