Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8140565 | Journal of Atmospheric and Solar-Terrestrial Physics | 2013 | 8 Pages |
Abstract
Preliminary breakdown pulses (PBP) of 26 positive and 104 negative cloud-to-ground (CG) lightning flashes observed in winter thunderstorms in Hokuriku region of Japan are analyzed. Pulses in PBP train are mainly bipolar. Zero-crossing time of each pulse is about 7Â us and total duration of each pulse train is about 1Â ms. PBPs in negative CG lightning are classified as “BIL type” (59 cases) and “BL type” (45 cases). “BIL type” PBP contains an intermediate stage with little electric field changes. The time interval between PBP and the first return stroke (PBP-RS interval) is on average 5.4Â ms for “BIL type” PBP, while that for “BL type” PBP is only 1.3Â ms. Ratio of peak amplitude of PBP to the first return stroke (PBP-RS ratio) is on average 0.47 and 0.44, respectively, for “BIL type” and “BL type” PBPs, but the ratio for “BIL type” PBP has a much wider distribution. It is speculated that the intermediate stage in “BIL type” PBP is caused by horizontal propagation of leader channel. PBPs in positive CG lightning are classified as +PBP (11 cases) and âPBP (15 cases) according to their initial polarities. +PBP and âPBP have similar distributions of both PBP-RS interval and PBP-RS ratio, but their value of PBP-RS interval is much larger and their value of PBP-RS ratio is much smaller than corresponding values of PBPs in negative CG lightning. It is speculated that different initial polarities of +PBP and âPBP in positive CG lightning are caused by different directions of channel propagation.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geophysics
Authors
Ting Wu, Yuji Takayanagi, Tsuyoshi Funaki, Satoru Yoshida, Tomoo Ushio, Zen-Ichiro Kawasaki, Takeshi Morimoto, Masahito Shimizu,