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A Positive Cloud‐to‐Ground Flash Caused by a Sequence of Bidirectional Leaders that Served to Form a Ground‐Reaching Branch of a Pre‐Existing Horizontal Channel
Author(s) -
Wu Bin,
Lyu Weitao,
Qi Qi,
Ma Ying,
Chen Lyuwen,
Jiang Ruijiao,
Zhu Yanan,
Rakov Vladimir A.
Publication year - 2021
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2020jd033653
Subject(s) - channel (broadcasting) , meteorology , connection (principal bundle) , geology , path (computing) , geodesy , geometry , physics , telecommunications , computer science , mathematics , computer network
Abstract High‐speed video and electric field change data were used to analyze the initiation and propagation of four predominantly vertical bidirectional leaders making connection to a predominantly horizontal channel previously formed aloft. The four bidirectional leaders sequentially developed along the same path and served to form a positive branch of the horizontal in‐cloud channel, which became a downward positive leader producing a 135‐kA positive cloud‐to‐ground (+CG) return stroke. The positive (lower) end of each bidirectional leader elongated abruptly at the time of connection of the negative (upper) end to the pre‐existing channel aloft. Thirty‐six negative streamer‐like filaments (resembling recently reported “needles”) extended sideways over ∼110 to 740 m from the pre‐existing horizontal channel at speeds of ∼0.5 to 1.9 × 10 7 m/s, in response to the injection of negative charge associated with the +CG.