摘要
利用常规资料、自动站加密资料、探空资料、ERA5再分析数据及多普勒天气雷达资料,对2021年4月30日影响浙北沿海的一次强对流天气过程进行分析。结果表明:(1)此次过程发生在高空冷涡及其槽后强劲的西北急流背景下,低空切变线和地面辐合线共同提供了抬升触发条件。(2)适当的对流抑制能量CIN、相对较低的自由对流高度LFC和较高的对流有效位能CAPE有利于形成上冷下暖的不稳定层结,深厚的垂直风切变配合中层干空气夹卷,使得强对流天气进一步发生、维持和发展。(3)此次阵风锋发展经历了3个阶段,产生阵风锋的雷暴主体发展强烈并引起地面大风时,存在强回波中心高度快速下降、后侧中层强入流、径向速度辐散场及速度模糊等特征。(4)强冷空气堆下沉形成气压梯度密集区和风温湿切变易造成雷暴大风天气,负变温中心及正变压中心对强对流有一定指示性。(5)阵风锋过境时常出现气压陡升、风速加大、风向突变、温度骤降,由于雷达观测距离限制,预报员需前期分析潜势,结合自动站要素与雷达信息共同研判。
Based on conventional observation data,encrypted data from automatic stations,radiosonde data,ERA5 reanalysis data,and Doppler weather radar data,a severe convective weather process affecting the coast of northern Zhejiang on April 30,2021,is analyzed.The results show that:(1)This process occurred in the background of the high-altitude cold vortex and the strong northwest jet behind its trough.The low-altitude shear line and the surface convergence line jointly provided the triggering conditions for uplift.(2)Appropriate CIN,relatively low LFC,and high CAPE were conducive to the formation of unstable stratification with cold upper and warm lower layers.Deep vertical wind shear combined with dry air entrainment in the middle layer further enabled the occurrence,maintenance,and development of severe convective weather.(3)The development of this gust front had gone through three stages.When the thunderstorm's main body generated a gust front that developed strongly and caused strong winds on the ground,there were characteristics such as a rapid drop in the height of the strong echo centre,a strong inflow in the rear middle layer,a radial velocity divergence field,and velocity ambiguity.(4)The sinking of a strong cold air pile formed a dense area of pressure gradient and wind temperature and humidity shear,which could easily lead to thunderstorms and gale weather.The negative and positive temperature variation centres had certain indications for strong convection.(5)During the transit of gust fronts,there was often an abrupt increase in atmospheric pressure and wind speed,sudden change in wind direction,and sudden drop in temperature.Due to the limitations of radar observation distance,forecasters needed to analyze the potential in the early stage and jointly studied and judged the automatic station elements and radar information.
作者
许欣欣
陈淑琴
徐哲永
曹宗元
XU Xinxin;CHEN Shuqin;XU Zheyong;CAO Zongyuan(Zhoushan Meteorological Bureau of Zhejiang Province,Zhoushan 316000)
出处
《气象科技》
2023年第3期441-453,共13页
Meteorological Science and Technology
基金
浙江省气象科技计划项目(2021ZD29)
舟山市气象局强对流创新团队共同资助。
关键词
雷暴大风
阵风锋
飑线
机制分析
thunderstorm and gale
gusty front
squall line
mechanism analysis
作者简介
许欣欣,女,1997年生,助理工程师,主要从事短期、短临天气预报工作,Email:xvxinx2016@163.com;通信作者:陈淑琴,Email:457920850@qq.com。
