我国喜马拉雅山区冰碛湖溃决危险性评价

Hazard Assessment of Moraine-dammed Lake Outburst Floods in the Himalayas,China

近年来,随着全球气候的变暖,冰碛湖溃决灾害正日益严重地威胁着人们生命和财产安全,在我国喜马拉雅山区尤其突出,对冰碛湖溃决灾害的研究也日益受到重视。基于大比例尺地形图、DEM和2004-2008年间的ASTER影像等数据,应用直接判别方法和基于事件树模型,通过确定不同类型冰碛湖溃决模式发生的定性描述和概率转换关系,对我国喜马拉雅山地区冰湖进行潜在危险性冰碛湖的识别和危险性冰碛湖溃决概率等级估算。结果显示,在2004-2008年间,我国喜马拉雅山区共有143个具有潜在危险性冰湖,其中溃决概率等级为"非常高"的44个、"高"的47个、"中"的24个、"低"的24个、"非常低"的4个,溃决概率为"非常高"和"高"等级的91个潜在危险性冰碛湖亟需进一步进行溃决风险评价。

With climate warming, Glacier Lake Outburst Floods （GLOFs） are increasingly threatening people and property, which has been intensively studied worldwide. This paper takes the Himalayas region of China as the study area, where the GLOFs have frequently occurred during the past decades. The 143 potentially dangerous glacier lakes were first identified by six indexes in the study area. Then, the probabilities of three types of possible breaching modes （i.e. ice avalanche, glacier slide, ice-core melting） were quantitatively graded on the basis of the criteria of the probabilities of moraine-dammed lake breaching modes. Breach probabilities of the 143 potentially dangerous glacier lakes were further calculated by means of decision-making trees methods.