Publication Date:
2019
Description:
Abstract
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 glacierised part, driven by temperature, correlates negatively with the runoff in the non‐glacierised 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 glacierised 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‐glacierised area, were modelled to isolate the effect of glacier cover on streamflow variability. The modelled relationship was then compared to a multi‐catchment dataset of gauged glacierised catchments in the European Alps. In a 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 multi‐catchment 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 glacierised catchments. Therefore, care should be taken to use a GCE curve for estimating and/or predicting interannual streamflow variability in glacierised catchments.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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