暴雨洪涝受灾人口与雨涝危险性指数关系模型研究

The relationship model between flood-hit population and rainstorm waterlogging risk index

建立可监测、可预报的雨涝危险性指数与暴雨洪涝受灾人口的关系模型,对暴雨洪涝灾前、灾中、灾后人口受灾情况快速评估具有重要意义。以湖北省为例,利用小时降水、日最大降水量、累积降水量与暴雨持续天数等气象资料以及水系、高程等孕灾环境资料,构建了雨涝危险性指数。结合历史洪涝受灾人口资料,建立基于雨涝危险性指数的暴雨洪涝受灾人口灾损曲线。按照重现期划分雨涝危险性等级,并通过计算不同重现期雨涝危险性指数的致灾阈值,建立危险性等级与受灾人口的定量关系模型。结果显示:(1)湖北省暴雨高危险区主要位于江汉平原以东,其次是鄂西南南部、江汉平原南部。(2)通过历史暴雨过程受灾情况比较,包含小时雨量和孕灾环境的雨涝危险性指数更能呈现暴雨过程的受灾程度。(3)湖北省暴雨洪涝受灾人口与雨涝危险性指数呈幂函数关系,年及暴雨过程实际受灾人口与拟合受灾人口的相关系数分别达0.800和0.891。(4)利用5 a、10 a和20 a三个重现期将雨涝危险性指数划分为三个等级,当雨涝危险性指数超20 a一遇时,预计受灾人口将达12万人以上。

Establishing the relationship model between the rainstorm waterlogging and flood-hit population is of great significance for the rapid assessment of the situation before,during,and after the disaster of rainstorm.Taking Hubei as an example,we established the rainstorm waterlogging risk index by using the meteorological data such as hourly precipitation,daily maximum precipitation,cumulative precipitation,and the continuous days of rainstorm,as well as the environmental data such as water system and elevation.Combined with the historical flood-hit population,we also established the disaster loss curve of the flood-hit population based on the waterlogging risk index.Then,we calculated the flood-hit population by using the threshold of waterlogging risk index according to the return period level.The results show that(1)the rainstorm waterlogging high-risk area in Hubei mainly locates in the eastern Jianghan Plain,followed by the south of southwestern Hubei and the southern Jianghan Plain.(2)By inspecting the disaster situation of historical rainstorm process,taking into account the rainstorm waterlogging risk index of favoring environment,can reflect the extent of disaster.(3)The flood-hit population was in a power function relationship with the rainstorm waterlogging risk index,and the correlation coefficients between the actual and the fitted flood-hit population in the year and during the rainstorm process reached 0.800 and 0.891,respectively.(4)The 5 a,10 a and 20 a return periods were used to divide the rainstorm waterlogging risk index into the three levels.When the rainstorm waterlogging risk index exceeds the return period of 20 a,it is estimated that the number of affected population will reach more than 120000.