The compensating effect of glaciers: Characterizing the relation between interannual streamflow variability and glacier cover
The compensating effect of glaciers: Characterizing the relation between interannual streamflow variability and glacier cover
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DOI：
10.1002/hyp.13603
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发表时间：
2019-11
影响因子：
3.2
通讯作者：
M. Tiel;I. Kohn;A. V. van Loon;K. Stahl
中科院分区：
文献类型：
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作者：
M. Tiel;I. Kohn;A. V. van Loon;K. Stahl
冰川融水不仅是稳定的水源，而且影响下游的水流动态。这些动态之一是水流的年际变化。冰川可以调节水流的变化，因为由温度驱动的冰川部分的径流与由降水驱动的流域非冰川部分的径流呈负相关，从而相互平衡。这也称为冰川补偿效应（GCE），假设该效应取决于相对的冰川覆盖。先前的研究发现，不同冰川流域的水流变化与冰川覆盖之间存在凸关系，在某个最佳冰川覆盖下水流变化最低。在这项研究中，我们的目标是重新审视这些先前发现的曲线，以找出年际径流变化和冰川覆盖之间是否存在普遍关系，这可能用于时空替代分析。此外，我们测试了以下假设：主要气候驱动因素（此处为降水和温度）围绕建议的最佳曲线进行切换。首先，对一组具有相同绝对冰川面积但不同非冰川化面积的虚拟嵌套流域进行建模，以隔离冰川覆盖对水流变化的影响。然后将建模的关系与欧洲阿尔卑斯山冰川化流域的多流域数据集进行比较。第三步，分析GCE曲线随时间的变化。模型结果显示，模拟曲线中存在凸关系和最佳值，与主要气候驱动因素的切换一致。然而，多流域数据和时间变化分析并没有表明普遍凸关系的存在。总体而言，我们得出的结论是，由于冰川流域中错综复杂的控制和随时间的变化，GCE 很复杂。因此，应注意使用 GCE 曲线来估计和/或预测冰川流域的年际水流变化。
Meltwater from glaciers is not only a stable source of water but also affects downstream streamflow dynamics. One of these dynamics is the interannual variability of streamflow. Glaciers can moderate streamflow variability because the runoff in the glacierized part, driven by temperature, correlates negatively with the runoff in the non‐glacierized part of a catchment, driven by precipitation, thereby counterbalancing each other. This is also called the glacier compensation effect (GCE), and the effect is assumed to depend on relative glacier cover. Previous studies found a convex relationship between streamflow variability and glacier cover of different glacierized catchments, with lowest streamflow variability at a certain optimum glacier cover. In this study, we aim to revisit these previously found curves to find out if a universal relationship between interannual streamflow variability and glacier cover exists, which could potentially be used in a space‐for‐time substitution analysis. Moreover, we test the hypothesis that the dominant climate drivers (here precipitation and temperature) switch around the suggested optimum of the curve. First, a set of virtual nested catchments, with the same absolute glacier area but varying non‐glacierized area, were modelled to isolate the effect of glacier cover on streamflow variability. The modelled relationship was then compared with a multicatchment data set of gauged glacierized catchments in the European Alps. In the third step, changes of the GCE curve over time were analysed. Model results showed a convex relationship and the optimum in the simulated curve aligned with a switch in the dominant climate driver. However, the multicatchment data and the time change analyses did not suggest the existence of a universal convex relationship. Overall, we conclude that GCE is complex due to entangled controls and changes over time in glacierized catchments. Therefore, care should be taken to use a GCE curve for estimating and/or predicting interannual streamflow variability in glacierized catchments.