Large-Scale Assessment of Delayed Groundwater Responses to Drought
Large-Scale Assessment of Delayed Groundwater Responses to Drought
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DOI：
10.1029/2019wr025441
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发表时间：
2020-02-01
影响因子：
5.4
通讯作者：
Stahl, K.
中科院分区：
文献类型：
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作者：
Hellwig, J.;de Graaf, I. E. M.;Stahl, K.
地下水是长期干旱期间淡水供应的重要资源，也是通过水文循环控制干旱传播的关键储存资源。目前的干旱监测缺乏对地下水干旱的大规模估计，但过去几年国家到全球规模模型的进展表明，它们现在可以成为研究和监测长期干旱期间水供应的宝贵工具。作为先决条件，模型需要能够充分描述地下水对降水的不同响应，以区分空间差异。在这里，我们为德国开发了一个高分辨率瞬态地下水模型，并测试了其代表地下水系统动态（重点关注干旱）的能力。根据水流分离基流和地下水头观测对模型结果进行验证，证实该模型能够普遍代表 40 年来的地下水头动态，但在模型分辨率太低而无法捕获当地山谷含水层的山区，模型性能较低。与地下水异常相关性最高的降水积累时间随着导水率和比产量的增加而增加，从德国中部高地的几个月到德国北部多孔含水层的几年。与这些差异相对应，不同的气象干旱类型导致德国各地模拟地下水反应不同。鉴于地下水作为资源的重要性，大规模地下水模型是未来研究干旱传播以及气候变化下地下水干旱的重要工具。
Groundwater is a vital resource for freshwater supply during extended droughts and also a key storage governing drought propagation through the hydrological cycle. Current drought monitoring lacks large-scale estimates of groundwater droughts, but progress of country-to-global-scale models in the last years suggests that they could now be valuable tools to study and monitor water availability during extended droughts. As a prerequisite the models would need to be able to depict the diverse groundwater response to precipitation well enough to distinguish spatial differences. Here we developed a high-resolution transient groundwater model for Germany and tested its ability for representing the groundwater system dynamics with a focus on droughts. Validation of model results against streamflow-separated baseflow and groundwater head observation confirmed the model's ability to generally represent the groundwater head dynamics over 40 years with lower model performance in mountainous regions where model resolution was too low to capture local valley aquifers. The precipitation accumulation time that has the highest correlation with groundwater anomalies increases with hydraulic conductivity and specific yield from few months in the Central German Uplands to several years in the porous aquifers of northern Germany. Corresponding to these differences, distinct meteorological drought types led to different simulated groundwater reactions across Germany. Given the importance of groundwater as a resource, large-scale groundwater models are important tools for future studies on drought propagation as well as groundwater drought under climate change.