拉萨春季一次雷暴天气过程分析  

Analysis of Spring Thunderstorm Process in Lhasa

作　　者：何晓红[1] 林志强[1] 罗布坚参[1] 唐叔乙[1] 次仁德吉[1] 

机构地区：[1]西藏自治区气象局气象台,拉萨850000

出　　处：《气象》2009年第5期55-60,I0004,共7页Meteorological Monthly

摘　　要：利用拉萨多普勒天气雷达、闪电定位仪、欧洲中心500hPa分析场及常规观测等资料,对2008年4月27—28日发生在拉萨的雷暴天气的环境条件和雷达回波特征进行了综合分析。结果表明:这次雷暴过程是在乌拉尔山冷空气南下,加剧了高原低涡切变辐合上升运动的发展,大气层结极不稳定的条件下产生的;雷达径向速度图和VAD风廓线均显示出非常明显的低层暖平流结构、低空急流及垂直风切变特征;γ中尺度气旋式涡旋扰动与环境垂直风切变的相互作用,导致雷暴云发展,回波顶增高,40dBz回波顶高伸展到7.0km左右;CAPE值、垂直风切变、γ中尺度气旋性扰动以及低层暖平流对拉萨雷暴天气预警、预报具有指示意义,给出了拉萨雷暴天气预报思路与着眼点。The weather environments and radar echo features of thunderstorm occurred on April 27th and 28th 2008 in Lhasa are analyzed by using Doppler radar data, lightning data and ECMWF data and conventional meteorological data and so on. The result showed that this thunderstorm in Lhasa was engendered by the cold air which came southward from Ural and strengthened the development of the unstable level and turbulence in Lhasa. Radial velocity map and VAD wind profiler both showed that there were obviously the low-level warm advection structure, low-level jet and vertical wind shears. The interaction between the γ-mesoscale cyclonic vortex disturbance and the environment vertical wind shears led to the developments of thunderstorm cloud and rising of echo top, of which the height of echo of 40 dBz reached to 7 km. The value of CAPE, the γ-mesoscale cyclonic vortex disturbance, vertical wind shears and low-level warm advection structure are good indices to the forecasting and warning of Lhasa thunderstorm. This paper gives the notion and the emphasis of the forecasting of thunderstorm in Lhasa.

关 键 词：雷暴 闪电频数 电流幅值 对流不稳定 雷达回波 

分 类 号：P458.121.1[天文地球—大气科学及气象学] V321.227[航空宇航科学与技术—人机与环境工程]