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以滦河流域多伦、承德、青龙和乐亭4个代表性气象站点1957—2010年日降水数据为基础资料,选取广义帕累托分布(Generalized pareto Distribution,GP)拟合各个气象站点春、夏、秋三季的降水距平百分率序列,并利用L-矩法估计参数,在此基础上采用二维Copula函数(Clayton和Gumbel-Hougaard分布函数)拟合春-夏、夏-秋降水距平百分率序列,依据降水距平百分率划分旱涝的标准进一步计算出各个站点旱涝交替和连旱连涝这两类旱涝组合事件发生的概率,结果表明:(1)Clayton和Gumbel-Hougaard分布函数均能较好地拟合季节间的降水距平序列;(2)青龙和乐亭较容易发生旱涝组合事件,春夏以持续干旱为主,夏秋以旱涝交替为主,夏秋季节间旱涝组合事件发生频率较高。
Based on the daily precipitation data from 1957 to 2010 at the four representative meteorological stations of Duolun, Chengde, Qinglong and Laoting in Luanhe River basin, the generalized Pareto Distribution (GP) Summer and autumn precipitation anomalies, and using L-moment method to estimate the parameters. Based on this, the two-dimensional Copula function (Clayton and Gumbel-Hougaard distribution function) was used to fit the spring-summer, summer-autumn precipitation anomalies Percentage series, according to the standard of precipitation anomaly percentage division of droughts and floods to further calculate the probability of each site drought and flood alternation and even drought and waterlogging combination event of two types of drought and flood. The results show that: (1) Clayton and Gumbel-Hougaard distribution function (2) Qinglong and Laoting were more prone to drought / flood event, and continued to be the main drought in spring and summer. In summer and autumn, drought and flood were the main alternations, and inter-summer rainfall Waterlogging events occur more frequently.