Glacier-dammed lake outburst events of Gornersee, Switzerland
Glacier-dammed lake outburst events of Gornersee, Switzerland
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DOI：
10.3189/172756507782202784
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发表时间：
2007-01-01
影响因子：
3.4
通讯作者：
Hock, Regine
中科院分区：
文献类型：
--
作者：
Huss, Matthias;Bauder, Andreas;Hock, Regine
瑞士戈尔纳湖是一个冰缘湖，几乎每年都会在几天之内从冰下流失。我们分析了 1950 年至 2005 年期间的湖泊溃决事件，以及 2004 年和 2005 年与湖泊排水相关的详细实地调查结果。后者包括湖泊几何形状、附近钻孔水压和冰川表面运动的测量。分布式温度指数融化模型与线性水库径流模型相结合，用于计算 Gornergletscher 流域的每小时流量，以便区分流量过程线中的融化/降水分量和爆发分量。这样，排水量和时间就确定了。从1950年开始，溃决洪水有明显的趋势是在融化季节提前发生，但湖泊流量没有变化。湖泊的峰值流量远低于使用 Clague 和 Mathews (1973) 提出的经验关系获得的值。 2004年和2005年湖泊流出过程线的形状有很大不同，表明排水机制不同。从水平衡考虑，我们推断冰川堰塞湖在 2005 年发生渗漏，始于湖泊溃决前 1 周。在排水过程中，多达一半的湖水暂时储存在冰川系统中，导致冰川表面大幅抬升。
Gornersee, Switzerland, is an ice-marginal lake, which drains almost every year, subglacially, within a few days. We present an analysis of the lake outburst events between 1950 and 2005, as well as results of detailed field investigations related to the lake drainage in 2004 and 2005. The latter include measurements of lake geometry, water pressure in nearby boreholes and glacier surface motion. A distributed temperature-index melt model coupled to a linear-reservoir runoff model is used to calculate hourly discharge from the catchment of Gornergletscher in order to distinguish between the melt/precipitation component and the outburst component of the discharge hydrograph. In this way, drainage volume and timing are determined. From 1950 there is a clear trend for the outburst flood to occur earlier in the melt season, but there is no trend in lake discharge volumes. Peak discharges from the lake lie significantly below the values obtained using the empirical relation proposed by Clague and Mathews (1973). The shapes of the 2004 and 2005 lake outflow hydrographs differ substantially, suggesting different drainage mechanisms. From water balance considerations we infer a leakage of the glacier-dammed lake in 2005, starting 1 week prior to the lake outburst. During the drainage events, up to half of the lake water is temporarily stored in the glacial system, causing substantial uplift of the glacier surface.