中国不同气候区的暴雨危险性分析

Hazard analysis of rainstorms in different climatic regions of China

暴雨的危险性评价是暴雨风险评价的重要环节,研究暴雨的危险性分布对于我国的暴雨洪涝灾害预测及制定合理的防灾减灾策略等具有重要意义。基于全国1961-2019年2 512个气象站点的日降水数据,计算每年的暴雨日数、雨量及雨强,使用核密度函数得到5、10、20、50 a这4个重现期下的各暴雨要素取值,进而通过ISODATA聚类将全国暴雨分为4个危险性等级。结果表明:随着重现期的增长,3个年暴雨要素不断增加。空间上年暴雨日数和雨量均呈现出由东南沿海向西部内陆减少的趋势,而年暴雨强度呈现出东部大、西部小,且东北部大于东南部的特征。8个气候区在3个重现期(10、20、50 a一遇)的年暴雨日数和雨量均值排序一致,均为华南地区最大,华中地区次之,西部干旱(半干旱)区最小;而8个气候区的年暴雨强度均值在不同重现期下的差异较大。ISODATA聚类分析结果显示华中、华南地区暴雨危险性最高,西部干旱(半干旱)区和青藏高原暴雨危险性最低。

The evaluation of the hazard of rainstorms is an important part of the risk evaluation of rainstorms.Studying the distribution of the danger of rainstorms is of great significance for the prediction of rainstorms and flood disasters in our country and the formulation of reasonable disaster prevention and mitigation strategies.Based on the daily precipitation data of 2512 meteorological stations across the country from 1961 to 2019,this paper calculated the rainstorm days,rainstorm rainfall and rainstorm intensity of each studied year,used the kernel density function to calculate the values of three rainstorm elements in the four return periods of 5 years,10 years,20 years and 50 years,and then divided the whole country into four different levels of rainstorm risk areas using ISODATA cluster analysis.The results show that with the increase of the return period,the value of three rainstorm elements increases.In space,both the annual rainstorm days and the annual rainstorm rainfall show a trend of decreasing from the southeast coast to the west inland,while the intensity of the rainstorm is larger in the east and smaller in the west,and is larger in the northeast than in the southeast.The mean annual rainstorm days and annual rainstorm rainfall of 8 climate zones in the three return periods(10 years,20 years and 50 years)are in the same order,all of which are the largest in south China,followed by central China,and the smallest in the western arid(semi-arid)zone.However,the average annual rainstorm intensity of the eight climate zones differs greatly in different return periods.The results of ISODATA cluster analysis show that the rainstorm danger is the highest in central China and south China,while the rainstorm hazard is the lowest in the western arid(semi-arid)zone and Qinghai-Tibet Plateau.