江苏近10a高架雷暴特征分析  

Analysis on the elevated thunderstorms in the past decade in Jiangsu

作　　者：曹舒娅 张静[2] 施丹平 李杨[2] CAO Shuya;ZHANG Jing;SHI Danping;LI Yang(Suzhou Meteorological Bureau,Jiangsu Suzhou 215000,China;Key Open Laboratory for Traffic Meteorology of China Meteorological Administration,Nanjing 210044,China;Jiangsu Meteorological Observcitory,Nanjing 210044,China)

机构地区：[1]苏州市气象局,江苏苏州215000 [2]江苏省气象台,南京210044 [3]中国气象局交通气象重点开放实验室,南京210044

出　　处：《气象科学》2018年第5期681-691,共11页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(41475042);江苏省科技厅科技支撑计划资助项目(BE2015731);北极阁基金资助项目(BJG201704).

摘　　要：对2007—2016年发生在江苏地区的冬半年雷暴进行特征分析,筛选出12次典型的高架雷暴天气过程,揭示江苏发生高架雷暴的时空分布特征和典型的环流形势,发现逆温层顶之上的不稳定浅层和上下层强垂直风切变分别为高架雷暴的发生提供弱热力不稳定和强动力不稳定条件。强垂直风切变、850 hPa附近强烈的锋生导致的锋面次级环流,高空槽前正涡度平流随高度增加以及高层辐散、低层辐合造成的抽吸作用,为高架雷暴的发生和维持提供逆温层之上的动力抬升条件。高架雷暴发生时高仰角反射率因子呈现出类似零度层亮带的环形特征,对流单体不断生成在圆环附近。初步归纳了江苏高架雷暴的预报着眼点:500 hPa先后高空槽东移,700 hPa有16 m·s^(-1)以上的西南急流,850 hPa切变线东伸,存在逆温层顶高于1. 5 km,逆温强度大于5℃的较强逆温,0～6 km垂直风切变超过18 m·s^(-1),700 hPa与500 hPa温度差在15℃以上以及700hPa的相对湿度高于80%,且比湿在5～6 g·kg^(-1)。Based on analysis on the characteristics of tliunderstorms in the past decade from 2007 to 2016 during winter half year in Jiangsu,twelve typical elevated thunderstorm processes were screened to reveal the temporal and spatial distribution characteristics and the typical circulation situation of elevated thunder storms occurred in Jiangsu.We found that unstable shUow layer on the top of tlie inversion layer and strong vertical wind shear provided weak themal instability and strong dynamical instability conditions.Strong vertical wind shear,frontal secondary circulation caused by frontogenesis at 850 hPa,the positive vorticity advection increased wit!i height in front of the upper trough,and the pumping action caused by upper divergence and lower convergence provide dynamical uplift condition above the top of t!ie inversion layer.On higher elevation angle echo present a circle which is like a zero band bright band.Convective monomer appeared constantly around the circle.We summarized forecast points of elevated thunder storms occurred in Jiangsu:two high troughs on 500 hPa move eastward successively;the speed of southwest jet is greater than 16 m+s 1 on 700 hPa,shear line on 850 hPa extends towards east;the heightof the top of the inversion layer is higher tlian 1.5 km;the inversion intensity is stronger tlian 5 O%0-6 km vertical wind shear is stronger than 18 m·s^-1%temperature contrast of 700 hPa and 500 hPa is bigger than 15 O and relative humidity of 700 hPa is higher than 80%,wtli its specific humidity at 5-6 g·kg^-1.

关 键 词：高架雷暴 逆温层 垂直风切变 锋生作用 伯努利方程 

分 类 号：P457[天文地球—大气科学及气象学]