一次阵风锋触发的强对流天气过程分析  

Analysis of a strong convective weather process triggered by a gust front

作　　者：苏继锋[1] 王海龙 刘勇 李帅 康汉青[2] SU Jifeng;WANG Hailong;LIU Yong;LI Shuai;KANG Hanqing(The 61Squad of the 94857 Unit of PLA,Wuhu 241007,China;Nanjing University of Information Science and Technology,Nanjing 210000,China)

机构地区：[1]94857部队61分队,安徽芜湖241007 [2]南京信息工程大学大气物理学院,江苏南京210000

出　　处：《大气与环境光学学报》2025年第1期34-46,共13页Journal of Atmospheric and Environmental Optics

基　　金：国家自然科学基金青年项目(41605091)。

摘　　要：利用常规观测数据、美国国家环境预报中心(NCEP)再分析数据、多普勒天气雷达和风廓线雷达数据及其二次开发产品数据,分析了2021年7月19日芜湖地区一次阵风锋及其触发的强雷暴所带来的大风和短时强降水天气过程。研究结果表明:(1)阵风锋附近径向速度场显示辐合特征明显,阵风锋在移动过程中遇到有利的环境场能够触发新的雷暴单体形成。(2)风廓线数据产品较好地反映了阵风锋过境前后垂直方向大气运动情况:锋前阶段,大气同时存在弱的上升和下沉运动;锋面初期,雷暴母体的下沉冷空气导致大气以下沉运动为主,风场切变层的最低高度有一个先下降再升高且切变层厚度变薄的趋势;锋面过境和锋后阶段,上升、下沉运动二者并存。(3)信噪比(SNR)能够直观地反映强对流天气过程中降水的开始、结束以及雨强的变化特征。受降水粒子和湍流影响,对流性降水的SNR在降水开始前10min就明显增大;降水开始后,对流性降水比稳定性降水的SNR要大,一般维持在50~65db,雨强极大值时SNR在55~70db。(4)利用风廓线数据二次开发计算的螺旋度(SRH)峰值出现时间比雨强极大值出现时间提前1~2h,可以作为预报强降水发生时间的一个参考因素。Based on conventional observation data,National Centers for Environmental Prediction(NCEP)reanalysis data,Doppler weather radar and wind profile radar data,as well as secondary development product data,the weather process of thunderstorm gale and short-time heavy precipitation triggered by a gust front in Wuhu area,China,on July 19,2021 was analyzed.The results show that:(1)The radial velocity field near the gust front has obvious convergence characteristics.When the gust front meets a favorable environmental field during its movement,it can trigger the formation of new thunderstorm cells.(2)The wind profile data products can reflect the vertical atmospheric motion before and after the passage of the gust front.There are weak rising and sinking motions at the same time in the atmosphere during the pre-frontal stage.In the early stage of the front,the sinking cold air of the thunderstorm parent causes the atmospheric subsidence to be the main movement,and the minimum height of the shear layer of wind field decreases first and then increases,and the thickness of the shear layer becomes thinner.During the transit and the post-frontal phases,there are both rising and sinking movements.(3)The signal-to-noise ratio(SNR)can directly reflect the beginning and end of precipitation and the changing characteristics of rain intensity during severe convective weather.As convective precipitation is affected by precipitation particles and turbulence,its SNR increases significantly 10 minutes before precipitation begins.After the beginning of precipitation,the SNR of convective precipitation is larger than that of stable precipitation,generally maintaining between 50 and 65 db,and between 55 and 70 db when the rain intensity is maximum.(4)The peak time of helicity(SRH),calculated by the secondary development of wind profile data,is 1–2 hours earlier than that of rain intensity maximum,which can be used as a reference factor to predict the occurrence time of heavy precipitation.

关 键 词：阵风锋 强对流 风廓线雷达 信噪比 螺旋度 

分 类 号：P458.3[天文地球—大气科学及气象学]