一次局地强对流天气的地闪特征分析

Analysis of the Cloud-to-ground Lightning Characteristics of a Local Severe Convective Weather

利用闪电定位系统的地闪资料、多普勒天气雷达资料、探空资料,对2016年8月7日梅州的一次局地强对流天气的地闪特征进行分析.分析表明:地闪空间分布特征呈明显的局地性,负闪在整个闪电活动过程占主要比例,正闪比峰值滞后于地闪的峰值约0.5 h,出现在雷暴的消亡阶段.地闪密集区域与雷达强回波区域相一致,闪电频数与同期最大回波顶高度、回波顶高度> 11 km格点面积呈显著正相关;多普勒雷达资料出现"逆风区"特征、组合反射率强度大、强回波垂直高度高、回波顶高度高、径向移动速度快等特征;地闪活跃时期,大气层结曲线呈明显的"上干下湿"型,中低空存在明显的垂直风切变.分析梅州地闪活动特征与同期气象资料的关系,有助于为该地区强对流天气的监测与预警提供依据.

Using Cloud-to-ground(CG)Lightning data of Guangdong Lightning Locating System(GDLLS),radar data and sounding data,this study mainly investigates lightning activities of a local strong convective weather in Meizhou on August 7,2016.The results show that the spatial distribution characteristics of CG lightning are obviously local,negative lightning accounts for the main proportion in the whole lightning activity process,and the peak value of positive lightning ratio lags behind the peak value of ground lightning for about 0.5h,which appears in the phase of thunderstorm extinction.The dense area of CG Lightning is consistent with the strong echo area of radar,and the lightning frequency is positively correlated with the maximum echo top height and echo top height>11km grid area in the same period;the Doppler radar data has the characteristics of“upwind area”,high combined reflectivity,high vertical height of strong echo,high echo top height and fast radial movement speed;during the active period of CG Lightning,the atmosphere is bent as the line is obviously“dry up and wet down”.There is obvious vertical wind shear in the middle and low level.Therefore,the analysis of the relationship between the characteristics of lightning activity and the meteorological data of the same period in Meizhou is helpful to provide a scientific basis for the monitoring and early warning of severe convective weather in this area.