摘要
冰湖的快速形成、扩张、溃决是气候变暖与冰川消融退缩的后果之一。大时空尺度的冰湖动态特征探究与预测、冰湖溃决洪水灾害数据库构建、冰湖溃决风险评估等工作,是理解区域环境变化和实施灾害防控管理的基础。以青藏高原为核心的“亚洲水塔”作为全球冰湖的主要分布区域之一,过去几十年的冰湖活动呈现了快速扩张特征和显著灾害效应。本研究梳理了近几年“亚洲水塔”冰湖变化以及溃决风险等方面的研究进展,结果显示喜马拉雅山东部和藏东南地区是当前“亚洲水塔”冰湖体量最大、绝对面积增长最快的区域。冰川末端接触湖是冰湖扩张的主要贡献者。1900—2020年间区域内共记录了145起冰碛湖溃决洪水,1980年代后的溃决频率呈增加趋势;冰坝湖溃决洪水共记录了183起,它们主要发生在喀喇昆仑山和西天山地区,具有流域聚集性和溃决周期性的特征。冰湖的不断扩张与溃决使得区域灾害风险增加,经过系统性评估所揭示的1499个极高或高危险性冰湖,其造成的潜在洪水淹没面积达到6353 km^(2),区域内大量的房屋、道路、桥梁、农田和水电设施等直接暴露在洪水路径中,居民生命财产和基础设施安全受到严重威胁。整体上,近十年“亚洲水塔”冰湖研究发展迅速,但仍然有一些需要深入研究的地方,包括统一标准的高精度冰湖编目,冰湖溃决洪水灾害与气候变暖之间的联系,以及流域尺度精细化的风险评估等。
The rapid formation,expansion,and outburst of glacial lakes are the prominent consequences of glob⁃al warming and glacier recession.Large-scale glacial lake mapping,glacial lake outburst flood(GLOF)compi⁃lations,and risk assessments are essential for understanding regional environmental changes and implementing effective disaster prevention and management strategies.Centered on the Tibetan Plateau,the Asian Water Tow⁃er is one of the major global glacial lake regions and has experienced rapid glacial lake expansion and significant disaster impacts over the past few decades.This study focuses on glacial lake changes,outbursts,and associated risks in the Asian Water Tower and summarizes recent advances in glacial lake research.The results show that:(1)The overall rate of glacial lake area expansion in the Asian Water Tower from 1990 to 2018[(31.6±4.0)km^(2)·(5a)-1]exceeded the average rate observed during 2018—2022[(22.7±8.5)km^(2)·(5a)-1].Proglacial lakes,accounting for 83%of the total area increase during 2018—2022,emerge as the primary contributor to the current expansion of glacial lakes in the Asian Water Tower,with changes mainly concentrated in the eastern Hi⁃malayas and southeastern Xizang.Under the future ice-free scenarios,a total of 15826 potential glacial lakes with areas exceeding 0.02 km^(2)are projected to emerge,covering an area of(2253.95±1291.29)km^(2)with a water volume of(60.49±28.94)km3.The western glacier-rich region is projected to experience a greater emer⁃gence of new and rapidly expanding lakes,although with a time lag compared to eastern regions such as the east⁃ern Himalayas and southeastern Xizang,due to different climate patterns.(2)From 1900 to 2020,145 credible moraine-dammed GLOFs were recorded in the region,with a marked increase in frequency after the 1980s.Spe⁃cifically,the average annual number increased from 1.5 GLOFs during 1981—1990 to 2.7 GLOFs during 2011—2020.Spatially,GLOF activity has intensified in southeastern Xizang and China-Nepal border area.Addition⁃ally,183 GLOFs stemming from ice-dammed lakes are documented,mainly concentrated in the Karakoram and western Tianshan Mountains,demonstrating watershed-scale clustering and periodic outbursts.(3)The ongoing expansion and frequent outbursts of glacial lakes have significantly increased disaster risk across the region.A systematic hazard assessment has identified 1499 glacial lakes classified as high or very high hazard level,poten⁃tially affecting a flood inundation area of 6353 km^(2).In terms of disaster-bearing bodies,approximately 55808 buildings,105 existing or planned hydropower projects,194 km^(2)of farmland,5005 km of roads,and 4038 bridges are vulnerable to potential GLOFs.Approximately 190000 peoples are directly exposed along GLOFprone pathways.Subsequently,85 lakes are classified as very high risk level and 113 as high risk level.The eastern Himalaya and southeastern Xizang exhibit the highest levels of GLOF hazard,exposure,and risk.This situation is exacerbated by the rapid expansion of glacial lakes,the increased frequency of GLOFs,the density of dangerous glacial lakes,and the significant potential disaster volume in the Asian Water Tower.These find⁃ings highlight the urgent need for more proactive GLOF prevention and mitigation efforts and the necessity of constructing a regionally coordinated and dynamic disaster management system.Overall,while glacial lake re⁃search in the Asian Water Tower has progressed rapidly over the past decade,critical challenges remain.These include the need for standardized and high-precision lake mapping,improved understanding of GLOF-climate re⁃lationships,and more refined and watershed-scale risk assessments.
作者
张太刚
王伟财
汪鑫
廖逸龙
安宝晟
ZHANG Taigang;WANG Weicai;WANG Xin;LIAO Yilong;AN Baosheng(Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China)
出处
《冰川冻土》
2025年第4期900-913,共14页
Journal of Glaciology and Geocryology
基金
西藏自治区科技计划项目(XZ202401ZY0064)
国家自然科学基金青年学生基础研究(博士研究生)项目(424B2002)资助。
关键词
冰湖
冰湖变化
冰湖溃决洪水
风险评估
亚洲水塔
glacial lake
glacial lake change
glacial lake outburst flood
risk assessment
Asian Water Tower
