Assessing water resource system vulnerability to unprecedented hydrological drought using copulas to characterize drought duration and deficit.
Assessing water resource system vulnerability to unprecedented hydrological drought using copulas to characterize drought duration and deficit.
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DOI：
10.1002/2015wr017324
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发表时间：
2015-11
影响因子：
5.4
通讯作者：
Hochrainer-Stigler S
中科院分区：
文献类型：
--
作者：
Borgomeo E;Pflug G;Hall JW;Hochrainer-Stigler S
全球气候模型表明，世界许多地区的蒸散量增加，风暴路径不断变化，水分输送量增加，这可能导致更长时间和更严重的干旱，但气候模型在模拟水文气候变量持续性方面的弱点以及与区域气候预测相关的不确定性意味着，基于气候模型输出的影响评估可能低估多年干旱的风险。在本文中，我们提出了一种基于脆弱性的方法来测试水资源系统对干旱的响应。我们产生了大量的合成径流系列不同的干旱持续时间和赤字，并使用它们作为水资源系统模型的输入。每个月的流量边际分布是通过自举历史数据生成的，而连续月份的联合概率分布是使用基于copula的方法构建的。干旱与更长的持续时间和更大的赤字比观察到的记录是通过扰动copula参数，并通过采用低流量的重要性抽样策略。通过这种方式，潜在的气候引起的每月水文持续性变化被纳入脆弱性分析。该方法适用于伦敦供水系统（英格兰），以调查在干旱条件下，严重的用水限制将需要施加。结果表明，水系统是脆弱的干旱条件以外的历史事件的范围。脆弱性评估结果与气候模型信息相结合，以比较各种备选水管理办法对日益长期和严重的干旱的脆弱性。使用copula函数灵活地模拟径流序列的时间依赖性评估水文持续性对水系统脆弱性的影响测试替代方案对干旱持续时间和赤字的鲁棒性
Global climate models suggest an increase in evapotranspiration, changing storm tracks, and moisture delivery in many parts of the world, which are likely to cause more prolonged and severe drought, yet the weakness of climate models in modeling persistence of hydroclimatic variables and the uncertainties associated with regional climate projections mean that impact assessments based on climate model output may underestimate the risk of multiyear droughts. In this paper, we propose a vulnerability‐based approach to test water resource system response to drought. We generate a large number of synthetic streamflow series with different drought durations and deficits and use them as input to a water resource system model. Marginal distributions of the streamflow for each month are generated by bootstrapping the historical data, while the joint probability distributions of consecutive months are constructed using a copula‐based method. Droughts with longer durations and larger deficits than the observed record are generated by perturbing the copula parameter and by adopting an importance sampling strategy for low flows. In this way, potential climate‐induced changes in monthly hydrological persistence are factored into the vulnerability analysis. The method is applied to the London water system (England) to investigate under which drought conditions severe water use restrictions would need to be imposed. Results indicate that the water system is vulnerable to drought conditions outside the range of historical events. The vulnerability assessment results were coupled with climate model information to compare alternative water management options with respect to their vulnerability to increasingly long and severe drought. Used copulas to flexibly model temporal dependence in streamflow sequences Assessed impact of hydrological persistence on water system vulnerability Tested the robustness of alternative options to drought duration and deficit