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Analyzing the transmission structures of long continuing current processes from negative ground flashes on the Qinghai-Tibetan Plateau


刊物全称

Journal of Geopgysical Research

论文作者

Xiangpeng Fan,Guangshu Zhang,Yanhui Wang,Yajun Li,Tong Zhang,Bin Wu

发表年度

2013

刊物类别

SCI

119

2050-2063

影响因子

3.1

通讯作者

Fan, XP

请求全文

fanxp@cams.cma.gov.cn

关键词

negative ground flashes, long continuing current process, overlap and progressive method

摘要

This paper presents a new overlap and progressive method using either a one-point charge model or a point dipole model for studying the electric field change data of lightning and tests the suitability of the proposed method by analyzing the slow electric field change of the long continuing current data from two negative ground flashes. The current measurements of the ground flashes are from the Composite Observing Experiment for Lightning project carried out in the Datong region of Qinghai Province, China, in 2009, obtained from field observations synchronized through high-precision GPS clocks at seven observation stations. Analysis shows that the time-averaged current can reach 800 A, and the current intensity relates to the height of the top of the return stroke before the continuing current process. The two current processes studied in this work neutralized a large amount of negative charge, 39.5C and 60.8C, respectively. The neutralized charges from the negative charge layer are typically at 2.5-4.7 km above ground. The intracloud transition of the positive leader is a complex process, and the horizontal propagation of the positive leader plays an important role in current duration as well as horizontally influencing the center of the electrical dipole moment with an obvious change of up to 3.0 km. The proposed analysis method is very useful compared to previous methods in terms of determining infinitesimal changes in long continuing currents. This work's new analysis method will help increase understanding of the fine physical processes of long continuing current processes.