Development characteristics of cloud-to-ground lightning with multiple grounding points

作     者：Bin FAN Ping YUAN Xuejuan WANG Yang ZHAO Jianyong CEN Yanling SU 

作者机构：Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic Engineering Northwest Normal University School of Atmospheric Physics Nanjing University of Information Science and Technology College of Physics and Information Engineering Shanxi Normal University 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2018年第61卷第8期

页      面：1127-1135页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：supported by the National Natural Science Foundations of China (Grants Nos. 11475139, 11365019 & 11605108) the Gansu Provincial Science and Technology Program (Grant No. 1506RJZA119) 

主　　题：Multiple grounding lightning High-speed camera Electric field changes Leader 

摘      要：Using the optical images of a cloud-to-ground lightning flash with multiple grounding points obtained by a highspeed video system in the Qinghai Province of China along with synchronous radiated electric field information, the propagation characteristic and the electric field change features of the leaders and the grounding behavior of discharge channels are *** addition, the two-dimensional velocity of the leader was estimated and its correlation with the time interval of the corresponding subsequent return stroke, and that with the peak current of return stroke are investigated. The results show that the average distance between the three obvious grounded points of the first return stroke channel is about 512.7 m, and the average time interval between the pulses of the corresponding electric field fast changes is 3.8 μs. Further, the average time interval between electric field pulses from the stepped leader is smaller than that of normal single grounding lightning. The observed lightning in our study has two main channels, namely the left and right channels. Based on our observations, it is clear that the dart leader comes close to the ground in case of the left channel after the first return stroke, but it fails to form a return ***, the right channel exhibits a relatively rare phenomenon in that the subsequent return stroke R2 occurred about 2.1 ms after the dart leader arrived at the ground, which was unusually long; this phenomenon might be attributed to the strong discharge of the first return stroke and insufficient charge accumulation near the grounded point in a timely manner. The two-dimensional velocities for the stepped leader of the two main channels are about 1.23×105 and 1.16×105 m s-1, respectively. A sub-branch of stepped leader for the left channel fails to reach the ground and develops into an attempt leader eventually; this might be attributed to the fact that the main branch connects considerably many sub-branches, which lea