Modeling of subglacial hydrological development following rapid supraglacial lake drainage.
Modeling of subglacial hydrological development following rapid supraglacial lake drainage.
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DOI：
10.1002/2014jf003333
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发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
Hubbard A
中科院分区：
文献类型：
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作者：
Dow CF;Kulessa B;Rutt IC;Tsai VC;Pimentel S;Doyle SH;van As D;Lindbäck K;Pettersson R;Jones GA;Hubbard A
冰上湖泊的快速排水在短时间内向格陵兰冰盖的河床注入了大量的水。这些水脉冲对基础水文系统发展的影响在很大程度上是未知的。为了解决这个问题，我们开发了一个湖泊排水模型，包括（1）由弹性水力顶推驱动的冰下径向通量元素和（2）通过连接的渠化和分布式系统的下游排水。在这里，我们提出的模型，并检查是否大量的，有效的冰下渠道可以形成在湖泊排水事件及其对周围分布系统的水压的影响。我们迫使该模型与现场数据从一个湖泊排水网站，70公里的终点罗素冰川在西格陵兰岛。模型的输出表明，有效的冰下渠道不容易形成在湖泊附近的快速排水，而是水主要是由瞬态湍流片和分布式系统疏散。湖泊排水后，河道生长，但不足以降低周围分布式系统的水压，除非整个区域存在预先存在的河道。我们的研究结果有影响的冰下水文系统的分析地区，快速湖泊排水提供了主要的机制，表面到床的连接。快速湖泊排水事件的冰下水文分析模型在快速湖泊排水期间和之后冰下河道的有限增长在河道增长有限的内陆地区分布式排水的持续性
The rapid drainage of supraglacial lakes injects substantial volumes of water to the bed of the Greenland ice sheet over short timescales. The effect of these water pulses on the development of basal hydrological systems is largely unknown. To address this, we develop a lake drainage model incorporating both (1) a subglacial radial flux element driven by elastic hydraulic jacking and (2) downstream drainage through a linked channelized and distributed system. Here we present the model and examine whether substantial, efficient subglacial channels can form during or following lake drainage events and their effect on the water pressure in the surrounding distributed system. We force the model with field data from a lake drainage site, 70 km from the terminus of Russell Glacier in West Greenland. The model outputs suggest that efficient subglacial channels do not readily form in the vicinity of the lake during rapid drainage and instead water is evacuated primarily by a transient turbulent sheet and the distributed system. Following lake drainage, channels grow but are not large enough to reduce the water pressure in the surrounding distributed system, unless preexisting channels are present throughout the domain. Our results have implications for the analysis of subglacial hydrological systems in regions where rapid lake drainage provides the primary mechanism for surface-to-bed connections. Model for subglacial hydrological analysis of rapid lake drainage events Limited subglacial channel growth during and following rapid lake drainage Persistence of distributed drainage in inland areas where channel growth is limited