Bias in streamflow projections due to climate‐induced shifts in catchment response
Bias in streamflow projections due to climate‐induced shifts in catchment response
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DOI：
10.1002/2015gl067326
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发表时间：
2016-02
影响因子：
5.2
通讯作者：
M. Saft;M. Peel;A. Western;J. Perraud;Lu Zhang
中科院分区：
文献类型：
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作者：
M. Saft;M. Peel;A. Western;J. Perraud;Lu Zhang
对气候变化对径流可能影响的定量评估的需求正在增加，概念性降雨径流模型是完成这项任务的重要工具。然而，这些模式在不断变化的气候条件下进行外推的能力值得怀疑。许多研究发现，模型预测能力随着气候条件的变化而下降，尤其是在预测干旱气候时。我们发现，模型技能仅在某些情况下下降，特别是当集水区的降雨径流过程由于气候驱动因素的变化而发生变化时。在降雨-径流关系因长期干旱而发生显著变化的集水区，径流一直被高估。相比之下，在降雨-径流关系在干旱期保持不变的集水区，模拟的径流是无偏的。这些结论不依赖于模型。我们的研究结果表明，目前对气候变化下径流的预测可能对一些预计降雨减少的地区未来的可用水量提供了过于乐观的评估。
Demand for quantitative assessments of likely climate change impact on runoff is increasing and conceptual rainfall‐runoff models are essential tools for this task. However, the capacity of these models to extrapolate under changing climatic conditions is questionable. A number of studies have found that model predictive skill decreases with changed climatic conditions, especially when predicting drier climates. We found that model skill only declines under certain circumstances, in particular, when a catchment's rainfall‐runoff processes change due to changed climatic drivers. In catchments where the rainfall‐runoff relationship changed significantly in response to prolonged dry conditions, runoff was consistently overestimated. In contrast, modeled runoff was unbiased in catchments where the rainfall‐runoff relationship remained unchanged during the dry period. These conclusions were not model dependent. Our results suggest that current projections of runoff under climate change may provide overly optimistic assessments of future water availability in some regions expecting rainfall reductions.