摘要
利用闪电定位资料叠加红外辐射亮温(TBB)、雷达资料,分析了山东连续两次强对流天气过程中出现的两个中尺度对流系统(MCS)、飑线、超级单体的闪电特征,结果表明:两个MCS正地闪比重很大,强盛阶段能达一半左右。地闪多分布在TBB小于220 K、对流发展旺盛且TBB梯度大的地带,地闪的分布可以很好地指示对流区;总地闪的变化与TBB极值和降水量有对应关系;对流云合并促进2016年6月14日中尺度对流系统(MCS)强烈发展,使其在初生发展阶段正闪居多并降雹。飑线中地闪多位于强回波区附近35~45 d Bz中;初生发展阶段地闪多集中于对流区,正闪多分布于云体倾斜度大的区域;成熟阶段地闪向层云区转移,多集中在低层入流边界后部,后侧入流急流上。超级单体在降雹前及降雹初期以正地闪为主,降雹前地闪频次迅速降低;降雹后,单体下沉气流增强且质心下降引发地闪猛增,最大反射率与地闪频数的变化趋势基本一致;最大反射率和回波顶高维持大值与地闪频数的骤减可以作为冰雹预测的指标。
Using the lightning location data superimposed by infrared radiation brightness temperature(TBB)and radar data,the lightning characteristics of two mesoscale convective systems(MCS),squall line and super single were analyzed.The results show that the ratio of positive ground flashes in two MCS is very large,which is about half as much in the strong stages.The ground flashes are mostly located in the areas with TBB less than 220 K strong convections and large TBB gradients,the distribution of ground flash can be a good indicator of convection zone.The change of total flash is related to TBB extremum and precipitation.The convergence of convective clouds promotes the development of MCS and makes positive flash increase fast in primary development stage.The ground lighting of squall line is located in regions with strong echoes between 35~45 dBz.In the early stage of cell development,the flash is more concentrated in the convection area and the positive flash is distributed in the cloud body tilt area.The ground lighting transfer to layer cloud,which is mostly concentrated at the back of the lower level inflow boundary and the downstream inflow jet stream.Flashes in the supercells were mainly positive before and during the early period of hail falling,and the frequency of flash decreased rapidly before hail.After hail,the increase of downward flow and decrease of the centroid of cells caused jumping of ground flashes,and the maximum reflectance was basically consistent with the change trend of the ground flash frequency.The continuous high value of maximum reflectivity and echo top height,as well as the sharply decrease of ground flash frequency can be used as the index of hail prediction.
作者
张琴
张晓
苟阿宁
环海军
张秀青
ZHANG Qin;ZHANG Xiao;GOU A-ning;HUAN Hai-jun;ZHANG Xiu-qing(Zibo Meteorological Bureau of Shandong Province Zibo 255048,China;State Key Laboratory of Numerical Modeling of Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics Beijing 100029,China;Wuhan Central Meteorological Observatory Wuhan 430074,China)
出处
《科学技术与工程》
北大核心
2018年第28期6-14,共9页
Science Technology and Engineering
基金
国家自然科学基金(41475041)
中国气象科学研究院灾害天气国家重点实验室重点课题(2014LASWA03)
山东省气象局课题(2017sdqxz06)资助
关键词
中尺度对流系统
地闪
飑线
超级单体
mesoscale convective system
ground flash
squall line
supercell
