Drought Analysis Based on Copulas
Drought Analysis Based on Copulas
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发表时间：
2011
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通讯作者：
Lu Chen;V. Singh;Shenglian Guo
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作者：
Lu Chen;V. Singh;Shenglian Guo
干旱会对一个国家或地区产生一系列复杂的经济、环境和社会负面影响。使用每月标准化降水指数（SPI）值确定干旱特征，即干旱持续时间、严重程度、间隔时间和最小 SPI 值。分别使用两个指数分布来模拟干旱持续时间和间隔时间；伽马分布用于模拟干旱严重程度；和广义帕累托分布来模拟最小 SPI 值。阿基米德和元椭圆族中的几个联结函数被应用于构建四维联合分布。选择汉江上游流域为例来说明系词。结果表明，Student copula 更适合所选区域的干旱分析。基于四维copula计算分析干旱概率和重现期。关键词表征；多元分布； SPI；系词
Droughts produce a complex set of negative economic, environmental, and social impacts across a country or region. Using monthly standardized Precipitation Index (SPI) values, drought characteristics, namely, drought duration, severity, interval time and minimum SPI values, were determined. Two exponential distributions were used to model drought duration and interval time, respectively; gamma distribution was used to model for drought severity; and generalized Pareto distribution to model minimum SPI value. Several copulas in the Archimedean and meta-elliptical families were applied to construct four- dimensional joint distributions. The upstream Han River basin was selected as an example to illustrate the copulas. Results indicates that the Student copula was more appropriate for drought analysis in the selected area. Drought probabilities and return periods were calculated and analyzed based on the four- dimensional copula. Keywordscharacterization; multivariate distribution; SPI; Copula