A theoretical drought classification method for the multivariate drought index based on distribution properties of standardized drought indices
A theoretical drought classification method for the multivariate drought index based on distribution properties of standardized drought indices
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DOI：
10.1016/j.advwatres.2016.04.010
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发表时间：
2016-06
影响因子：
4.7
通讯作者：
Z. Hao;F. Hao;V. Singh;Youlong Xia;W. Ouyang;Xinyi Shen
中科院分区：
文献类型：
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作者：
Z. Hao;F. Hao;V. Singh;Youlong Xia;W. Ouyang;Xinyi Shen
干旱指数通常用于描述干旱的不同性质，人们已经认识到需要将多个干旱指数结合起来进行准确的干旱监测。近年来，在多种干旱指数线性组合的基础上，开发了多种多元干旱指数，用于综合干旱监测，整合各种来源的干旱信息。对于干旱业务管理，通常需要确定干旱分类的干旱严重程度阈值，以便在干旱事件期间触发缓解反应，以帮助利益攸关方和决策者进行决策。基于单变量干旱指数的干旱分类方法研究较多，但基于多变量干旱指数的干旱分类方法研究较少，主要是由于缺乏对其分布特性的了解。本文提出了一种基于多指标线性组合的多元干旱指数理论分类方法。根据标准化干旱指数的分布特性，导出了线性组合指数的理论分布，可用于百分位法对干旱进行分类。以美国加利福尼亚州的气候区划数据为例，说明了基于标准化降水指数（SPI）、标准化土壤湿度指数（SSI）和标准化径流指数（SRI）的LDI干旱分类方法的应用。与经验方法的比较结果表明，该方法具有较好的分类效果。
Drought indices have been commonly used to characterize different properties of drought and the need to combine multiple drought indices for accurate drought monitoring has been well recognized. Based on linear combinations of multiple drought indices, a variety of multivariate drought indices have recently been developed for comprehensive drought monitoring to integrate drought information from various sources. For operational drought management, it is generally required to determine thresholds of drought severity for drought classification to trigger a mitigation response during a drought event to aid stakeholders and policy makers in decision making. Though the classification of drought categories based on the univariate drought indices has been well studied, drought classification method for the multivariate drought index has been less explored mainly due to the lack of information about its distribution property. In this study, a theoretical drought classification method is proposed for the multivariate drought index, based on a linear combination of multiple indices. Based on the distribution property of the standardized drought index, a theoretical distribution of the linear combined index (LDI) is derived, which can be used for classifying drought with the percentile approach. Application of the proposed method for drought classification of LDI, based on standardized precipitation index (SPI), standardized soil moisture index (SSI), and standardized runoff index (SRI) is illustrated with climate division data from California, United States. Results from comparison with the empirical methods show a satisfactory performance of the proposed method for drought classification.