基于地区线性矩法的大汶河流域极值降雨频率分析

Frequency Analysis of Extreme Rainfall in Dawen River Basin Based on Regional L-Moments Method

以山东省大汶河流域为例,采用M-K检验法对6、12、24 h和3 d的年极值降雨资料进行一致性分析,在此基础上,采用地区线性矩法推求站点暴雨设计值,将区域设计值结果与单站线性矩法结果进行对比分析,并绘制了大汶河流域50年一遇暴雨设计值的空间分布图。结果表明,可将大汶河流域划分为3个水文气象一致区,最优分布线型以广义极值分布(GEV)为主;单站线性矩法与地区线性矩法结果的差距(平均绝对相对误差)随样本系列长度的增加而减小,且重现期越大差距越大;大汶河流域暴雨设计值的空间分布不均,但各时段分布态势基本相似。

Taking Dawen River Basin in Shandong Province as an example, Mann-Kendall method was used to analyze the consistency of the 6 h, 12 h, 24 h and 3 d annual extreme rainfall data. The regional linear moment method was used to infer the design value of the site rainstorm, and the regional design value was compared with the single-station linear moment method. The spatial distribution map of the design value of the 50-year rainstorm in Dawen River Basin was drawn. The results show that the Dawen River Basin can be divided into 3 hydrometeorological homogeneous regions, and the optimal distribution frequency linetype is dominated by the generalized extreme-value distribution(GEV). The difference(mean absolute relative error) between the results of single-station L-moment frequency analysis method and regional L-moments frequency analysis method decreases with the increase of the length of the sample series, and the larger the return period is, the greater the gap is;The spatial distribution of the designed rainstorm values in Dawen River Basin is not uniform, but the distribution trend of each period is basically similar.