摘要
2019年8月4日,恩施州鹤峰县躲避峡流域因短时强降雨诱发中小河流域山洪暴发,发生13人伤亡的重大灾害事故。本研究利用常规资料,数值预报再分析资料,地面加密雨量站、多普勒雷达和卫星监测资料以及相关水文资料,围绕导致山洪暴发的短时强降雨形成的天气形势背景和中小尺度对流系统特征、水文耦合特征、地形影响等进行综合分析,揭示其致灾成因。结果表明,(1)中高纬度维持“两槽一脊”的大环流背景,对流层中低层受热带低值系统扰动影响,加上高温高湿高能的大气层结不稳定,对午后出现强对流天气有利;(2)鹤峰典型的迎风坡地形抬升作用下在边界层形成局地中小尺度辐合系统,加上躲避峡流域东北—西南带状的峡谷地形,使得峡谷内形成了向后传播持续较长具有MCS模态特征的强对流回波带,是躲避峡流域出现短时强降雨的直接原因;(3)短时强降雨发生后,窄而陡峭的峡谷地形下,致洪雨量阈值偏低,水流快速汇集,上涨速度快、水流速度大,上游遇突发性短时强降雨时,下游人员因来不及避险是导致伤亡事故的重要原因;(4)水文耦合分析结果得出,躲避峡流域洪峰出现一般滞后于短时强降雨2~3 h,故针对短时强降雨诱发中小河流域山洪致灾阀值研究,做好水雨情监测和及时预警,对防范中小河流域灾害事故具有积极意义。
On August 4th,2019,mountain floods in Hefeng County,Enshi Prefecture were caused by short-term heavy rainfall,a major disaster accident with 13 casualties occurred.This research used conventional data,numerical forecast and reanalysis data,ground encryption rainfall station,Doppler radar and satellite monitoring data,and related hydrological data,weather situation background and small and medium-scale convection system characteristics around the formation of short-term heavy rainfall leading to flash floods,hydrological coupling characteristics,comprehensive analysis of topographic effects was conducted to reveal the cause of the disaster.The results showed that,(1)Maintain the large circulation background of“two grooves and one ridge”at medium and high latitude,and the middle and low troposphere is affected by the tropical low-value system disturbance,coupled with the instability of high temperature,high humidity and high energy,which is conducive to the occurrence of strong convective weather in the afternoon;(2)Crane peak typical windward slope terrain uplift under the boundary layer form local small and medium-scale convergence system,and avoid the gorge valley northeast-southwest belt valley terrain,makes the canyon formed backward transmission continuous long strong convective echo zone with MCS mode characteristics,is the direct cause to avoid short-term heavy rainfall in the gorge basin;(3)After the occurrence of short-term heavy rainfall,under the narrow and steep canyon terrain,the flood rainfall threshold is low,the water flow is quickly collected,the rise speed is fast and the water flow speed is large.In sudden short-term heavy rainfall,downstream personnel are an important cause for casualties to avoid risk;(4)The results of hydrologic coupling analysis showed that avoiding the flood peak in the gorge basin generally lags behind the occurrence of the short-term heavy rainfall by 2~3 hours,therefore,the study of mountain flood valve in the short-term heavy rainfall induced medium river basin monitoring and timely early warning is of positive significance to preventing disasters and accidents in the medium river basin.
作者
罗菊英
周建山
王珊珊
聂池祥
LUO Ju-ying;ZHOU Jian-shan;WANG Shan-shan;NIE Chi-xiang(Enshi Prefecture Meteorological Bureau,Enshi 445000,Hubei,China;Wuhan Central Meteorological Station,Wuhan 430074,China;Enshi Prefecture Hydrological and Water Resources Survey Bureau,Enshi 445000,Hubei,China)
出处
《湖北农业科学》
2022年第S01期74-81,共8页
Hubei Agricultural Sciences
基金
中国气象局预报员专项“雷达估算降水在山洪灾害预警中的应用分析(CMAYBY2020-083)”
关键词
山区
中小河流域
山洪灾害
mountain areas
in the small river basin
mountain flood disaster
作者简介
罗菊英(1972-),女,湖北恩施人,本科,高级工程师,主要从事中短期(短临)预报方法研究,(电话)18007269520,(电子信箱)396606423@qq.com。
