Triangulation of sprites, associated halos and their relation to causative lightning and micrometeors

Sprite halos were recently identified as an impulsive but spatially diffuse phenomenon that sometimes occurs just prior to, but distinct from, sprites. The lack of discernible spatial structure and the temporal development sequence in halos differs markedly from the highly structured bodies and tend...

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Bibliographic Details
Published in:Journal of Geophysical Research 2001-06, Vol.106 (A6), p.10
Main Authors: Wescott, E M, Stenbaek-Nielsen, H C, Sentman, D D, Heavner, M J, Moudry, D R, Sao Sabbas, F T
Format: Article
Language:English
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Summary:Sprite halos were recently identified as an impulsive but spatially diffuse phenomenon that sometimes occurs just prior to, but distinct from, sprites. The lack of discernible spatial structure and the temporal development sequence in halos differs markedly from the highly structured bodies and tendrils and the complex development sequences of sprites. However, both phenomena are thought to result from an electric field due to charge moment changes usually associated with large positive cloud-to-ground (CG) lightning but also following negative CG flashes. Three-dimensional triangulations of sprites and sprite halos were made between stations in South Dakota and Wyoming in August 1999 during the NASA Sprites99 balloon campaign. Halos were found to have a Gaussian 1/e diameter of ~66 km and 1/e thickness of ~4 km. Comparison with the location of the underlying lightning strokes, as recorded by the National Lightning Detection Network (NLDN), confirms that the horizontal position of sprites may be laterally offset by as much as 50 km from the underlying parent lightning discharge, as has been previously reported. (Author)
ISSN:0148-0227