| 摘要: |
| 【目的】 针对指数分布在超定量洪水序列计算时存在适线灵活性不足的缺点，应用改进线性矩法和广义Pareto分布研究超定量洪水序列频率的计算问题。【方法】 以陕西省延河流域无定河赵石窑站超定量洪水序列为例，采用Poisson分布拟合超定量洪水发生次数，用常规线性矩法和改进线性矩法估计广义Pareto分布参数，并分别进行超定量序列频率分析。根据复合极值理论，结合Poisson分布和广义Pareto分布获得年最大超定量洪水分布。采用Pearson-Ⅲ分布，对赵石窑站年最大洪水序列频率进行分析。选用离(残)差平方和最小值(OLS)准则对上述3种方法计算的洪水频率进行对比分析。【结果】 改进线性矩法估计的OLS值小于常规线性矩法；广义Pareto分布的OLS值小于Pearson-Ⅲ分布。【结论】 改进线性矩法估计参数的精度高于常规线性矩法；建议在水利工程规划中采用广义Pareto分布进行超定量洪水频率分析计算。 |
| 关键词: 超定量洪水 洪水频率分析 广义Pareto分布 改进线性矩法 年最大超定量洪水 Poisson分布 |
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| 基金项目:国家自然科学基金项目（50879070,50579065）;西北农林科技大学青年学术骨干支持计划和优秀博士论文基金项目 |
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| Application of generalized Pareto distribution in POT flood series frequency analysis |
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| Abstract: |
| 【Objective】 Considering the bad agility of exponential distribution on curve fitting of Peak over threshold(POT) flood frequency analysis,the modified L-moments and generalized Pareto distribution were used to study POT flood series frequency.【Method】 Choosing the POT flood series from Zhaoshiyao site of Wuding river of Yanhe basin of Shaanxi Province,we fitted the number of POT flood with Poisson distribution,calculated the parameters of generalized distribution by normal L-moments and modified L-moments method,and then executed the frequency analysis of POT flood series separatly,Subsequently,according to multivariate compound extreme theory,the distribution of the largest POT series was obtained using Pearson-Ⅲ distribution executes frequency analysis of annual maximum flood series.In order to execute comparative analysis of the three methods,the OLS values of different frequency curve were compared.【Result】 By comparing the OLS values of frequency curve,it shows that the OLS value of modified L-moments is less than the OLS value of normal L-moments.The OLS value of Generalized Pareto distribution is less than the OLS value of Peartson-Ⅲ distribution.【Conclusion】 Modified L-moments is better than normal L-moments in parameters estimation,and should be used in generalized Pareto distribution to analyze POT flood frequency in projecting hydraulic engineering. |
| Key words: POT flood flood frequency analyze generalized Pareto distribution modified L-moments annual maximum POT flood Poisson distribution |
