Evaluation of water-energy balance frameworks to predict the sensitivity of streamflow to climate change
Evaluation of water-energy balance frameworks to predict the sensitivity of streamflow to climate change
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DOI：
10.5194/hess-16-1419-2012
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发表时间：
2012-05
影响因子：
6.3
通讯作者：
M. Renner;R. Seppelt;C. Bernhofer
中科院分区：
文献类型：
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作者：
M. Renner;R. Seppelt;C. Bernhofer
径流的长期平均变化是水文和水资源管理中的一个主要问题。有一些简单的分析方法可以用来评估径流对气候变化的敏感性。这些都是基于布迪科假说，该假说假定长期平均径流量可以根据气候条件，即通过年平均降水量和蒸发需求来预测。最近，Tomer和Schilling(2009)提出了一个生态水文学概念来区分气候变化和流域特征变化对径流的影响。我们将这一概念与水和能量平衡的耦合考虑联系起来。我们证明，这个概念相当于假设即使在气候条件变化的情况下，年实际蒸散量与降水量之比以及实际蒸散量与潜在蒸散量之比之和也是恒定的。在这里，我们使用这一假设来推导出径流对气候敏感问题的解析解。我们展示了，根据这一假设，气候敏感性将如何受到不同气候条件和流域实际水文响应的影响。最后，将该方法的性质和意义与已有的Budyko灵敏度方法进行了比较，并通过三个实例进行了说明。这两种方法之间的最大差异似乎出现在限制条件下。具体地说，基于生态水文学概念的敏感性框架不遵守水和能量的限制，而Budyko方法通过增加径流对编码流域特征的集水区参数的敏感性来考虑限制条件。我们的发现不支持在接近水或能源极限的条件下应用生态水文学概念，相反，我们建议基于Budyko框架进行修正。
Long term average change in streamflow is a major concern in hydrology and water resources management. Some simple analytical methods exist for the assessment of the sensitivity of streamflow to climatic variations. These are based on the Budyko hypothesis, which assumes that long term average streamflow can be predicted by climate conditions, namely by annual average precipitation and evaporative demand. Recently, Tomer and Schilling (2009) presented an ecohydrological concept to distinguish between effects of climate change and basin characteristics change on streamflow. We relate the concept to a coupled consideration of the water and energy balance. We show that the concept is equivalent to the assumption that the sum of the ratio of annual actual evapotranspiration to precipitation and the ratio of actual to potential evapotranspiration is constant, even when climate conditions are changing. Here, we use this assumption to derive analytical solutions to the problem of streamflow sensitivity to climate. We show how, according to this assumption, climate sensitivity would be influenced by different climatic conditions and the actual hydrological response of a basin. Finally, the properties and implications of the method are compared with established Budyko sensitivity methods and illustrated by three case studies. It appears that the largest differences between both approaches occur under limiting conditions. Specifically, the sensitivity framework based on the ecohydrological concept does not adhere to the water and energy limits, while the Budyko approach accounts for limiting conditions by increasing the sensitivity of streamflow to a catchment parameter encoding basin characteristics. Our findings do not support any application of the ecohydrological concept under conditions close to the water or energy limits, instead we suggest a correction based on the Budyko framework.