基于系统聚类和PPCC检验法的极端暴雨风险区划

Extreme Rainstorm Risk Zoning Based on Systematic Clustering and Probability Plot Correlation Coefficient Test Methods

水文频率分析是评估自然灾害、极端水文气象事件的有效方法。以河北省山洪防治区为例,结合系统聚类分析和概率点据相关系数(PPCC)检验法,分析区域水文频率,计算出不同重现期的暴雨频率估计值,并对研究区不同时段不同重现期下的暴雨高风险进行区划分析。结果表明,研究区划分为四个一致区,其中Ⅰ区适用对数皮尔逊-Ⅲ型分布,Ⅱ区适用耿贝尔分布,Ⅲ、Ⅳ区适用二参数正态分布。暴雨频率估计值随重现期和时段的增加而增大,呈现东南向西北递减的趋势;各时段不同重现期下的暴雨最大值均出现在中南部太行山区和东北部燕山南麓,最小值分布在西北部地区。同一时段不同重现期暴雨频率估计值的空间分布形态相似,但估计值大小随重现期的增加而增大;而同一重现期下不同时段下暴雨频率估计值表现出不同的空间差异性。研究成果有助于河北山区防洪减灾工作的展开。

Hydrologic frequency analysis is an efficient way of evaluating natural disaster and extreme hydrometeorological events. Taking the flash flood control area of Hebei Province as the study area, the regional hydrologic frequency analysis was carried out by combining the systematic clustering method and probability plot correlation coefficient(PPCC) test method. The extreme rainstorm frequency of different return periods was calculated. The high rainstorm risk zoning maps of different rainfall scale under different return periods were analyzed. The results show that the study area was divided into four regions, in which the logarithmic Pearson-Ⅲ distribution is applied in region Ⅰ, the Gumbel distribution is applied in region Ⅱ, and the two-parameter normal distribution is applied in region Ⅲ and Ⅳ. The extreme rainstorm frequency increased with the increase of return period and rainfall duration, and showed a decreasing trend from southeast to northwest. The maximum rainstorm occurred in the southern part of Taihang mountains and northeast part the of Yanshan Mountains, and the minimum rainstorm occurred in the northwest of the study area. The spatial distribution patterns of estimated rainstorm frequency in different return periods of the same period were similar, but the estimated value increased with the increase of return periods. In the same return period, the estimated rainstorm frequency of different periods showed different spatial differences. The results is helpful to flood control and disaster prevention for mountainous area in Hebei Province.