| 摘要: |
| 【目的】构建二、三维干旱特征变量重现期的联合分布模型，对实际的干旱变量重现期范围进行估计，为旱情预报提供参考。【方法】采用4种对称和5种非对称的Archimedean Copula函数，构建黑河流域上游莺落峡、梨园站和正义峡3个水文站干旱历时、干旱烈度和干旱烈度峰值的二、三维联合分布模型；通过拟合度评价，选取Frank和Clayton Copula函数，对黑河流域的联合重现期和同现重现期进行计算，分析黑河流域重现期的空间演变规律。【结果】单变量的重现期理论值介于二、三维变量联合重现期与同现重现期之间；当单变量重现期理论值为5年时，采用干旱历时与干旱烈度的二维联合分布模型，推求的莺落峡、梨园站以及正义峡3个水文站的实际单变量重现期分别为4～7，2～6 及4～7年。【结论】Copula函数能够较好地用于构建黑河流域干旱特征变量的重现期分布模型。 |
| 关键词: 黑河流域 Copula函数 干旱变量联合分布模型 频率分析 重现期 |
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| 基金项目:国家自然科学基金重点项目（91125010）；高等学校学科创新引智计划资助项目（B12007） |
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| Frequency analysis of drought in Heihe river basin using Copula function |
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| Abstract: |
| 【Objective】 The joint distribution model based on two- and three-dimensional drought variables was built to estimate intervals of return periods of actual drought variables,which benefits drought forecast.【Method】 The joint distribution model of two- and three-dimensional drought variables,drought durations,drought severities and peak intensities,was structured based on 4 symmetric and 5 asymmetric Archimedean Copulas for Yingluoxia,Liyuan and Zhengyixia hydrological stations at upstream of Heihe river.Fitting degrees were evaluated to select Frank and Clayton Copulas and the joint return period and co-occurrence return period were calculated to ascertain the intervals of return period in Heihe river basin.【Result】 The return period of single variable ranged between the joint return period and co-occurrence return period by two- and three-dimensional variables.When the theoretical return period of single variable was 5 years,the return periods of Yingluoxia,Liyuan and Zhengyixia calculated by the two-dimension joint distribution model using drought duration and drought severity were 4-7,2-6 and 4-7 years,respectively.【Conclusion】 This study showed that Copulas functions can describe the return period of multivariate joint distributions of drought variables in Heihe river basin. |
| Key words: Heihe River basins Copula function joint distribution frequency analysis return period |
