一次由线状风暴和阵风锋引发的致灾大风成因  

Causes of a damaging gale event triggered by linear convective storms and gust fronts

作　　者：褚颖佳 高帆 张永婧[1,2] 郑丽娜 胡鹏[1,2] CHU Yingjia;GAO Fan;ZHANG Yongjing;ZHENG Lina;HU Peng(Key Laboratory for Meteorological Disaster Prevention and Mitigation of Shandong,Jinan 250031,China;Jinan Meteorological Bureau,Jinan 250102,China)

机构地区：[1]山东省气象防灾减灾重点实验室,山东济南250031 [2]济南市气象局,山东济南250102

出　　处：《海洋气象学报》2023年第2期53-63,共11页Journal of Marine Meteorology

基　　金：山东省自然科学基金项目(ZR2021MD010,ZR2022MD088);山东省自然科学基金青年项目(ZR2021QD028);山东省气象局预报员专项(SDYBY2017-05,SDYBY2019-05,SDYBY2020-04);山东省气象局科研项目(2022sdqxm07)。

摘　　要：2018年6月13日,多条线状风暴和阵风锋造成山东多地出现致灾大风,基于常规、加密气象观测资料、卫星云图和多普勒天气雷达资料,对此次大风成因进行了分析。结果表明:(1)冷涡后部横槽转竖引导冷空气叠加在低层暖脊之上,850 hPa与500 hPa温差高达34.7℃,同时925~600 hPa的干层与地面至925 hPa的近饱和层相叠置,上下层大气之间温、湿差异显著,形成强热力不稳定,持续并增强的低层逆温层使不稳定能量得到积累,显著干层和低层强温度垂直递减率为夹卷和蒸发冷却过程提供了有利条件。(2)线状风暴各生命期强阵风是由内嵌其中的普通单体或超级单体下击暴流所引发。单体间下沉气流合并使地面大风的影响范围和强度有所增大。强阵风均伴随较强降雨和降雹,雨滴和冰雹的拖曳是产生下击暴流的重要原因,极大风速与5 min降水量具有正向相关性,青岛34.8 m·s^(-1)的极端大风出现时5 min降水量达19 mm。(3)山东东南部的初生对流在地面辐合线、海风锋、对流云街上被接连触发,遇阵风锋后生命史延长,得以并入到主风暴,使风暴发展壮大,而风暴中的下沉气流又驱动多股阵风锋加速向南推进,增强地面风速,阵风锋与风暴主体之间存在相互促进机制。在对流潜势较高的条件下,需关注边界层辐合线对对流的触发作用。Several linear convective storms and gust fronts triggered a damaging gale event in multiple places in Shandong on 13 June 2018.Based on conventional and intensive meteorological observation data,satellite cloud imageries,and Doppler radar data,the causes of the gale event are analyzed.The results are as follows.(1)The horizontal trough behind the cold vortex turns to longitudinal style and guides cold air to superimpose on the warm ridge in the lower atmosphere.The temperature difference between 850 hPa and 500 hPa is as high as 34.7℃.At the same time,the dry layer of 925-600 hPa superimposes on the nearly saturated layer from the surface to 925 hPa,resulting in a significant difference in temperature and humidity between the upper and lower atmospheres,as well as strong thermal instability.The continuous and intensified inversion layer in the lower layer helps accumulate unstable energy.The significant dry layer and the high vertical temperature lapse rate of the lower atmosphere provide favorable conditions for the entrainment and evaporative cooling process in the storm.(2)The gales in each life stage of the linear storm are caused by the downbursts in the embedded ordinary cells or supercells.The combination of downdrafts between cells increases the influence range and intensity of the surface gales.Strong gales in each life stage are accompanied by heavy precipitation and hails.The dragging of raindrops and hails is an important reason for downbursts.The maximum wind speed is positively correlated with the 5-minute precipitation,and the 5-minute precipitation reaches up to 19 mm when the extreme gust of 34.8 m·s^(-1) appears at Qingdao station.(3)The primary convective cells in the southeast of Shandong are triggered successively at the surface convergence line,sea breeze front,and convective cloud street.After encountering the gust fronts,the primary convective cells are prolonged and are incorporated into the main storms,which accordingly grow stronger.The downdrafts in the storms,in turn,drive gust fr

关 键 词：线状对流风暴 阵风锋 超级单体 下击暴流 致灾性大风 

分 类 号：P458.3[天文地球—大气科学及气象学]