基于概率统计的河北省暴雨致灾风险评估

Risk Assessment of Heavy Rain in Hebei Province Based on Probability Statistics

根据河北省142个气象观测站点逐日逐小时降水资料,提取降水量、降水强度、降水历时、降水分布4个暴雨过程评价指标,基于百分位分布和概率统计方法,建立暴雨致灾风险评估模型.结果表明,暴雨致灾风险与降水量、降水强度、降水历时以及降水分布等因素紧密相关,其中降水量影响最大,其次为降水强度、降水历时;暴雨过程发生频次随暴雨致灾能力综合指数E值呈现先增大后减少的偏正态分布趋势,在2.0~3.5之间发生次数最多;暴雨致灾概率和历史个例平均直接经济损失与风险等级呈正相关关系,致灾风险Ⅳ级暴雨过程致灾概率小,造成的平均直接经济损失低,Ⅲ、Ⅱ级暴雨过程致灾概率和平均直接经济损失依次增大,Ⅰ级暴雨灾害过程致灾概率最大,可达92%,造成直接经济损失最大,危险性极高.

With the daily and hourly precipitation data from 142 meteorological observation stations in Hebei Province,four evaluation indexes of rainstorm process including precipitation,precipitation intensity,precipitation duration,and precipitation distribution were extracted.A model for risk assessment of rainstorm disaster was established based on percentiles distribution and probability statistics methods.The results showed that the disaster risk of heavy rain is closely related to factors such as precipitation,precipitation intensity,precipitation duration,and precipitation distribution.Among them,precipitation has the largest impact,followed by precipitation intensity and precipitation duration.The frequency of historical torrential rain processes occurred showed a partial normal distribution trend that first increased and then decreased with the change of the comprehensive index of rainstorm disaster-causing ability(E),and occurred most frequently between 2.0 and 3.5.The disaster probability of heavy rain and the average direct economic loss of historical individual cases were positively correlated with the risk level.The disaster caused by disaster risk probability of class IV rainstorm process is small,and the average direct economic loss is low.The hazard probability and the average direct economic loss of class III and II rainstorm process increase sequentially.The class I rainstorm disaster process has the greatest disaster probability,reaching 92%,causing the greatest direct economic loss and extremely dangerous.