玉屏暴雨与致灾暴雨特征及乡镇“三个叫应”阈值确定

The Characteristics of Rainstorm and Disaster-causing Torrential Rain in Yuping and the Determination of the"Three Call For Response"Threshold by Township

该文使用玉屏县国家站及乡镇考核站点2014—2020年暴雨天气过程日降水量、逐小时降水量及灾情数据,统计分析玉屏县暴雨天气及致灾暴雨天气过程降水特点,对本地“三个叫应”阈值进行检验,并提炼乡镇“三个叫应”阈值。结果表明:①新店镇暴雨频次逐年变化幅度不大,而田坪镇变化幅度最大,朱家场镇次之。②全县在5—7月出现暴雨的频次较高,6月达到峰值,而朱家场镇暴雨频次的峰值出现在7月。③在所有暴雨天气过程中,短时强降水多出现在夜间,致灾分为持续性降水或平缓降水致灾、暴雨叠加致灾、短时强降水致灾。当玉屏县境内出现连续4 d以上降水且累计雨量达到100 mm左右,或10 mm·h^(-1)左右降水持续5~9 h,将可能出现灾情。暴雨叠加分为空间叠加及时间叠加,玉屏县辖区2次暴雨时间间隔小于1 d,将极易引发相关灾害。空间叠加为玉屏县中南部3 h出现50 mm降水叠加岑巩上游暴雨,玉屏县中南部将可能出现灾情。④对“三个叫应”阈值进行检验,结果表明各乡镇的致灾雨强并不统一,因此制定分乡镇的“三个叫应”阈值,3 h阈值为40~60 mm。

This paper uses the daily precipitation,hourly precipitation and disaster data of the Yuping County National Station and the township assessment site from 2014 to 2020 to analyze the rainfall characteristics of Yuping’s regional rainstorm weather and the disaster-causing rainstorm weather process.The threshold value of“Three Call For Response”is tested,and the threshold of“Three Call For Response”of the townships is refined.The results show that:①The annual heavy rain in Xindian has little change from year to year,and Tianping has the largest change,followed by Zhujia;②The frequency of heavy rain in the whole county is higher from May to July,reaching the peak in June,while the peak of the number of heavy rains in Zhujiachang occurs in July;③In all regional heavy rain,short-term heavy rain mostly occurs at night,which can be divided into continuous precipitation or gentle precipitation to cause disaster,heavy rain superimposed disaster,and short-term heavy rain.When precipitation occurs in Yuping for more than 4 consecutive days and the accumulated rainfall reaches about 100 mm,or the precipitation lasts for 5 to 9 hours at about 10 mm per hour,disasters may occur.Heavy rain superposition is divided into space superposition and time superposition.If the interval between two heavy rains in Yuping area is too short,the current interval is determined to be 1 day,which will easily cause related disasters.The spatial superimposition is that there will be a 50 mm precipitation in the middle and south of Yuping for 3 hours,and there will be heavy rain in the upper reaches of Cengong,and there will be a disaster in the middle and south of Yuping.④According to the disaster situation and the rain intensity of each town’s heavy rain duration,the“Three Call For Response”thresholds were tested.The disaster-causing rain intensity of the townships is not uniform.Therefore,the“Three Call For Response”thresholds for each town were established,and the 3h threshold is 40~60 mm.