Positive leader characteristics from high-speed video observations

Marcelo M.F. Saba; Kenneth L. Cummins; Tom A. Warner; E. Philip Krider; Leandro Z.S. Campos; Mauricio G. Ballarotti; Osmar Pinto; Stacy A. Fleenor

doi:10.1029/2007GL033000

Positive leader characteristics from high-speed video observations

Marcelo M.F. Saba, Kenneth L. Cummins, Tom A. Warner, E. Philip Krider, Leandro Z.S. Campos, Mauricio G. Ballarotti, Osmar Pinto, Stacy A. Fleenor

Institute of Atmospheric Physics

Research output: Contribution to journal › Article › peer-review

101 Scopus citations

Abstract

Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values rage from 0.3 to 6.0 × 10⁵ ms^-1 with a mean of 2.7 × 10⁵ ms^-1. Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.

Original language	English (US)
Article number	L07802
Journal	Geophysical Research Letters
Volume	35
Issue number	7
DOIs	https://doi.org/10.1029/2007GL033000
State	Published - Apr 16 2008

ASJC Scopus subject areas

Geophysics
General Earth and Planetary Sciences

Access to Document

10.1029/2007GL033000

Cite this

@article{0247ecd052b846edb789f7530ab45bcb,

title = "Positive leader characteristics from high-speed video observations",

abstract = "Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values rage from 0.3 to 6.0 × 105 ms-1 with a mean of 2.7 × 105 ms-1. Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.",

author = "Saba, {Marcelo M.F.} and Cummins, {Kenneth L.} and Warner, {Tom A.} and Krider, {E. Philip} and Campos, {Leandro Z.S.} and Ballarotti, {Mauricio G.} and Osmar Pinto and Fleenor, {Stacy A.}",

year = "2008",

month = apr,

day = "16",

doi = "10.1029/2007GL033000",

language = "English (US)",

volume = "35",

journal = "Geophysical Research Letters",

issn = "0094-8276",

publisher = "American Geophysical Union",

number = "7",

}

TY - JOUR

T1 - Positive leader characteristics from high-speed video observations

AU - Saba, Marcelo M.F.

AU - Cummins, Kenneth L.

AU - Warner, Tom A.

AU - Krider, E. Philip

AU - Campos, Leandro Z.S.

AU - Ballarotti, Mauricio G.

AU - Pinto, Osmar

AU - Fleenor, Stacy A.

PY - 2008/4/16

Y1 - 2008/4/16

N2 - Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values rage from 0.3 to 6.0 × 105 ms-1 with a mean of 2.7 × 105 ms-1. Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.

AB - Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values rage from 0.3 to 6.0 × 105 ms-1 with a mean of 2.7 × 105 ms-1. Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.

UR - http://www.scopus.com/inward/record.url?scp=45549105911&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45549105911&partnerID=8YFLogxK

U2 - 10.1029/2007GL033000

DO - 10.1029/2007GL033000

M3 - Article

AN - SCOPUS:45549105911

SN - 0094-8276

VL - 35

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 7

M1 - L07802

ER -

Positive leader characteristics from high-speed video observations

Abstract

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this