郑州地区一次冷锋后高架雷暴天气过程特征及成因分析  

Characteristics and causes of an elevated thunderstorm case happening after a cold front in Zhengzhou area

作　　者：崔慧慧 CUI Hui-hui(Zhengzhou Meteorological Office of He′nan Province,Zhengzhou 450005,China)

机构地区：[1]郑州市气象台,河南郑州450005

出　　处：《气象与环境学报》2017年第6期34-41,共8页Journal of Meteorology and Environment

基　　金：河南省科技攻关项目"大城市暴雨;强对流精细预报与监测预警技术研究"(162102310056);河南省强对流创新团队和中国气象局华中区域气象中心科技发展基金项目(QY-Z-201302)共同资助

摘　　要：利用常规气象观测资料和美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)逐6 h再分析资料对2015年早春郑州地区一次高架雷暴天气过程的特征进行分析,探讨此次雷暴天气过程的成因。结果表明:地面冷垫、850 hPa和700 hPa强盛的暖湿急流及500 hPa高空槽为此次郑州地区高架雷暴天气过程的产生提供了有利的动力、热力和水汽条件,850—700 hPa之间的强垂直风切变和700—500 hPa之间较大的温差均表明逆温层以上对流不稳定度增大,有利于高架雷暴天气的产生。低空强比湿平流和负水汽通量散度为高架雷暴天气提供了丰富的水汽条件。高架雷暴天气过程发生前,700 hPa与500 hPa的θ_(se)差值Δθ_(se)大于0℃,表明700 hPa以上大气为对流不稳定,低层湿位涡的第一分量(MPV1)为负值又表明大气为湿对称不稳定,强雷暴落在对流不稳定区和MPV1负值区,因而此次高架雷暴天气过程是由对流不稳定和湿对称不稳定共同作用产生的。地面冷垫以上的暖湿气团逐步加强,进一步加剧了逆温层以上大气的层结不稳定度。通过与历史个例对比分析可知,郑州地区两次高架雷暴天气过程共同之处为:500 hPa高空槽前辐散气流的抽吸作用、低空切变线和低空急流左侧的辐合上升运动、地面冷垫的抬升作用均为高架雷暴天气预报的着眼点。Based on conventional meteorological observation and the NCEP(National Centers for Environmental Prediction)6hourly1°×1°reanalysis data,the characteristics and causes of an elevated thunderstorm weather process happening in Zhengzhou area in early spring of2015were analyzed.The results showed that the ground cold pad,850hPa and700hPa strong warm jet and trough at500hPa provide favorable dynamic,thermal and moisture conditions for the occurrence of an elevated thunderstorm.A large vertical wind shear between700hPa and850hPa and the large temperature difference between700hPa and500hPa show that there is a strong convective instability above the inversion layer,which is helpful for the occurrence of this elevated thunderstorm.A negative moisture vapor flux divergence and strong humidity advection at the low level provide an abundant water vapor for the elevated thunderstorm.Before the occurrence of thunderstorm,Δθse between700hPa and500hPa is above0℃,and the atmosphere above700hPa is in a convective instability condition.The negative MPV1(Moist Potential Vorticity)at the low level indicates that there is a moist symmetric instability condition in this layer,and the strong thunderstorm falls just in the convective instability zone and the negative area of MPV1.All these results indicate that this elevated thunderstorm is the result of joint interaction between convective instability and moist symmetrical instability.The warm air mass on the ground cold pad is gradually strengthened.It further exacerbates the atmospheric stratification stability above the inversion layer.By comparing with historical cases,it is found that the two elevated thunderstorm weather processes over Zhengzhou have some common features.The pumping action in front of500hPa troughs,low level shear line,the convergence ascending motion at the left side of the low level jet and the uplift of the ground cold pad should be the focus to forecast the elevated thunderstorms.

关 键 词：高架雷暴 冷垫 低空急流 对流不稳定 湿对称不稳定 

分 类 号：P446[天文地球—大气科学及气象学]