一次雷暴过程云闪放电通道三维结构及其始发阶段特征的观测分析  

Observation and analysis of 3D structure of the intracloud lightning discharge channel and characteristics of its initial stage in a thunderstorm process

作　　者：宋琳 王曙东[2] 姚文 孟繁辉 李杰[4] 孙豪 章俊超 SONG Lin;WANG Shudong;YAO Wen;MENG Fanhui;LI Jie;SUN Hao;ZHANG Junchao(Qingdao Meteorological Disaster Protection Technology Center,Qingdao 266003,China;Public Meteorological Service Center of China Meteorological Administration,Beijing 100081,China;Yingkou Meteorological Bureau,Yingkou 115001,China;The Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation center on Forecast and Evaluation of Meteorological Disaster(CIC-FEMD)/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]青岛市气象灾害防御技术中心,青岛266003 [2]中国气象局公共气象服务中心,北京100081 [3]营口市气象局,营口115001 [4]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心/中国气象局气溶胶与云降水重点开放实验室,南京210044

出　　处：《电波科学学报》2023年第2期355-364,共10页Chinese Journal of Radio Science

基　　金：国家重点研发计划(2020YFB1600103);中国气象局公共气象服务中心创新基金(M2021017)。

摘　　要：为了定量描述云闪三维通道的结构演变,通常建立闪电脉冲辐射源与雷达回波强度之间的关系,还可为雷电预警提供有益参考依据.本文基于南京地区的低频三维闪电辐射源定位系统,观测研究了2018-08-03一次强对流天气过程中典型的三次云闪,利用波形互相关算法来确定闪电脉冲到达不同测站的时间差这一定位技术,对云闪的脉冲辐射源点进行三维空间定位,并对其放电通道三维结构特征进行详细分析.结果表明:南京地区此次雷暴过程的三次云闪其始发位置均从6 km高度开始,并近似垂直向上发展,平均发展速度为2.9×10^(5)~3.6×10^(5)m/s,在到达10 km高度后,呈现水平发展趋势,而随后的水平发展阶段位于两个高度或集中于同一高度;三次云闪脉冲始发点处的回波强度均小于30 dBZ,且脉冲辐射源点几乎都是从强回波区的上部或者靠近弱回波区处始发,并在弱回波区继续垂直向上发展.利用波形互相关时间差定位技术对云闪的脉冲辐射源进行空间定位,可以较为清晰地描绘云闪的三维通道结构,进而分析得到南京地区云闪始发阶段脉冲辐射源与雷达回波强度之间的定量映射关系.In order to quantitatively describe the lightning channel characteristics of 3D channel intracloud(IC)lightning,we establish the relationship between the lightning radiation sources and the radar echo at the synchronization time,and provide a useful reference for lightning early warning.Based on the data from the 3D low-frequency magnetic lightning mapping array in Nanjing,three typical ICs in a severe convective weather system are observed and studied.The main results are as following:the initial processes of the three ICs are almost vertical upward from about 6 km to the height of about 10 km and then approximately develop horizontally;the average propagation speed is about 2.9×10^(5)−3.6×10^(5) m/s;there are two ICs that discharge in two different heights range with different propagation direction,and the other one is in the same height range with the same propagation direction;the lightning radiation sources are basically concentrated in the strong radar echo above 30 dBZ.Time difference of arrival(TDOA)method via cross-correlation technology are used to spatially locate the radiation source of the ICs,which can map the 3D channel structure of the flash,especially the characteristics of the initial stage in real time,and the quantitative mapping relationship between the radiation sources and the radar echo in the initial stage of the ICs in Nanjing area is also obtained.

关 键 词：低频磁场 三维闪电定位 雷达回波 闪电始发 辐射源 

分 类 号：P427.32[天文地球—大气科学及气象学]