Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage

Abstract By conducting comprehensive observation on the rarely triggered positive lightning flashes, two cases of upward negative leaders were quantitatively investigated with simultaneous data of current, optical, and electromagnetic field changes at fine time resolution. The impulsive channel curr...

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Main Authors: Yunjiao Pu, Rubin Jiang, Xiushu Qie, Mingyuan Liu, Hongbo Zhang, Yanfeng Fan, Xueke Wu
Format: Article
Language:English
Published: Wiley 2017-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2017GL074228
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author Yunjiao Pu
Rubin Jiang
Xiushu Qie
Mingyuan Liu
Hongbo Zhang
Yanfeng Fan
Xueke Wu
author_facet Yunjiao Pu
Rubin Jiang
Xiushu Qie
Mingyuan Liu
Hongbo Zhang
Yanfeng Fan
Xueke Wu
author_sort Yunjiao Pu
collection DOAJ
description Abstract By conducting comprehensive observation on the rarely triggered positive lightning flashes, two cases of upward negative leaders were quantitatively investigated with simultaneous data of current, optical, and electromagnetic field changes at fine time resolution. The impulsive channel current associated with the initial leader stepping involved pulse interval, peak, charge of 19.1 μs, 122.3 Å, 465.9 μC, and 20.3 μs, 58.4 Å, 267.2 μC, for the two cases, respectively. The negative charge of an individual step was nearly an order of magnitude larger than that of the positive leader step in triggered lightning. The upward negative stepped leader branches shortly after initiation, and consequently, the stepping‐caused current pulses became multipeaked, wider, and more frequent in waveforms. The main leader tip propagated at an average speed of 2.10 × 105 m/s, while its partial speed fluctuated a lot as was significantly influenced by the behaviors of subbranches development.
format Article
id doaj-art-80d957a3a3d942e687040c09dee3623f
institution DOAJ
issn 0094-8276
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language English
publishDate 2017-07-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-80d957a3a3d942e687040c09dee3623f2025-08-20T03:10:28ZengWileyGeophysical Research Letters0094-82761944-80072017-07-0144137029703510.1002/2017GL074228Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stageYunjiao Pu0Rubin Jiang1Xiushu Qie2Mingyuan Liu3Hongbo Zhang4Yanfeng Fan5Xueke Wu6Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics Chinese Academy of Sciences Beijing ChinaCollege of Atmospheric Sciences Lanzhou University Lanzhou ChinaAbstract By conducting comprehensive observation on the rarely triggered positive lightning flashes, two cases of upward negative leaders were quantitatively investigated with simultaneous data of current, optical, and electromagnetic field changes at fine time resolution. The impulsive channel current associated with the initial leader stepping involved pulse interval, peak, charge of 19.1 μs, 122.3 Å, 465.9 μC, and 20.3 μs, 58.4 Å, 267.2 μC, for the two cases, respectively. The negative charge of an individual step was nearly an order of magnitude larger than that of the positive leader step in triggered lightning. The upward negative stepped leader branches shortly after initiation, and consequently, the stepping‐caused current pulses became multipeaked, wider, and more frequent in waveforms. The main leader tip propagated at an average speed of 2.10 × 105 m/s, while its partial speed fluctuated a lot as was significantly influenced by the behaviors of subbranches development.https://doi.org/10.1002/2017GL074228upward negative leadertriggered lightningpositive lightningstepped leaderbranching
spellingShingle Yunjiao Pu
Rubin Jiang
Xiushu Qie
Mingyuan Liu
Hongbo Zhang
Yanfeng Fan
Xueke Wu
Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage
Geophysical Research Letters
upward negative leader
triggered lightning
positive lightning
stepped leader
branching
title Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage
title_full Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage
title_fullStr Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage
title_full_unstemmed Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage
title_short Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage
title_sort upward negative leaders in positive triggered lightning stepping and branching in the initial stage
topic upward negative leader
triggered lightning
positive lightning
stepped leader
branching
url https://doi.org/10.1002/2017GL074228
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AT rubinjiang upwardnegativeleadersinpositivetriggeredlightningsteppingandbranchingintheinitialstage
AT xiushuqie upwardnegativeleadersinpositivetriggeredlightningsteppingandbranchingintheinitialstage
AT mingyuanliu upwardnegativeleadersinpositivetriggeredlightningsteppingandbranchingintheinitialstage
AT hongbozhang upwardnegativeleadersinpositivetriggeredlightningsteppingandbranchingintheinitialstage
AT yanfengfan upwardnegativeleadersinpositivetriggeredlightningsteppingandbranchingintheinitialstage
AT xuekewu upwardnegativeleadersinpositivetriggeredlightningsteppingandbranchingintheinitialstage