青藏高原冰湖溃决灾害隐患识别、发育规律及危险性评价

    Identification, development law and risk assessment of the hidden dangers of glacial lake outburst disasters on the Qinghai-Tibet Plateau

    • 摘要: 青藏高原是全球冰湖溃决灾害发生最频繁的区域之一,冰湖溃决对人类及工程建设安全造成严重威胁。以2015—2018年Landsat 8 OLI_TIRS等遥感影像及数据为基础,对青藏高原40000余条冰川10 km范围内且面积大于900 m2的冰湖进行了遥感解译,分析了冰湖分布与发育特征,建立了冰湖溃决隐患的识别指标体系,利用突变级数法(CPM)对隐患点进行了危险性分级评价。结果表明:①青藏高原发育冰湖16481处,海拔分布在5000~5500 m之间的冰湖占总量的43.69%;面积集中在100~500 km2之间的占总量的47.40%;行政分布上主要分布在西藏自治区,有12664个,占总量的76.84%;流域上主要分布在雅鲁藏布江流域,有8321个,占总量的50.49%。②识别出冰湖灾害隐患点369个,其中低危险点126个,中危险点177个,高危险点66个。③冰湖溃决隐患点面积多为0.1~0.2 km2;海拔主要分布在5000~5500 m之间;与母冰川距离大多小于100 m;冰碛坝宽度一般小于300 m,背水坡坡度大多小于50°;冰湖溃决隐患点的母冰川冰舌端坡度分布在10°~20°之间;绝大多数冰湖溃决的方向朝向北方。

       

      Abstract: The Qinghai-Tibet Plateau is one of the most frequent glacial lake outburst floods(GLOFs)areas in the world.The GLOF poses a serious threat to the safety of human beings and engineering construction.Based on the remote sensing images and data of Landsat 8 OLI_TIRS from 2015 to 2018, this paper interprets the GLOFs where located within 10 km range of more than 40000 glaciers and its area is greater than 900 m2.This paper analyzes the distribution and development characteristics of glacial lakes, establishes the identification index system of GLOFs, and evaluates the hidden danger points by the catastrophe progression method(CPM).The following results the shown.①There are 16481 glacial lakes in Qinghai-Tibet Plateau, which are mainly distributed at 5000~5500 m above sea level, accounting for 43.69% of the total.The area is concentrated between 0.01~0.05 km2, accounting for 47.40% of the total.In terms of administrative distribution, the Tibet Autonomous Region has the largest number of glacial lakes, 12664, accounting for 76.84% of the total.In terms of basin distribution, the Yarlung Zangbo River Basin has the largest number of glacial lakes, with 8321, accounting for 50.49% of the total.②369 potential GLOFs were identified, including 126 low-risk points, 177 medium risk points and 66 high-risk points.③The area of hidden danger of GLOFs is mostly 0.1~0.2 km2.The altitude is mainly distributed between 5000 ~5500 m above sea level.The distance between the hidden danger point and the mother glacier is less than 100 m, and the width of the moraine dam is mostly less than 300 m.The backwater slope is mostly less than 50°, the slope of the ice tongue of the mother glacier is between 10° and 20°, and most of the GLOFs burst to the north direction.

       

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