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On negative Sprites and the Polarity Paradox
Author(s) -
Chen Alfred BingChih,
Chen Han,
Chuang ChiaWen,
Cummer Steven A.,
Lu Gaopeng,
Fang HuiKuan,
Su HanTzong,
Hsu RueRon
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083804
Subject(s) - sprite (computer graphics) , light emission , physics , polarity (international relations) , thunderstorm , polarity reversal , meteorology , astrophysics , atmospheric sciences , environmental science , optics , chemistry , voltage , computer science , computer vision , cell , quantum mechanics , biochemistry
Energetic positive and negative cloud‐to‐ground (CG) flashes are both capable of producing sprites. Negative CGs typically outnumber the positive ones by 10 to 1. However, >99.9 % of reported sprites were found to be initiated by positive CGs—thus the polarity paradox. Here, sprites recorded by the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) mission were analyzed along with extremely low‐frequency band magnetic field data to resolve this paradox. Approximately twenty‐five percent of the sprites are found to be associated with negative CG lightning. “Negative” sprites mainly congregate in the latitudinal regions below 20°, while positive sprites scatter up to 50°. The ISUAL negative sprites are evidently beyond the observable ranges of the ground sites reported in previous studies. Hence, the sprite polarity paradox is likely a selection effect of the middle‐ to high‐altitudinal observation sites. The charge moment changes and accompanying transient luminous events of sprites were also examined and found to be polarity dependent.