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Analyzing the transmission structures of long continuing current processes from negative ground flashes on the Qinghai‐Tibetan Plateau
Author(s) -
Fan Xiangpeng,
Zhang Guangshu,
Wang Yanhui,
Li Yajun,
Zhang Tong,
Wu Bin
Publication year - 2014
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd020402
Subject(s) - current (fluid) , plateau (mathematics) , dipole , electric field , moment (physics) , lightning (connector) , peak current , meteorology , physics , geodesy , geology , mathematics , mathematical analysis , power (physics) , electrode , classical mechanics , quantum mechanics , electrochemistry , thermodynamics
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.