@InProceedings{CamposSaCuAnPiGu:2014:PhChMu,
author = "Campos, Leandro Zanella de Souza and Saraiva, Antonio Carlos
Varela and Cummins, Kenneth L. and Antunes, Larissa and Pinto Jr.,
Osmar and Guedes, Dailton Gilberto",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {The University of
Arizona} and {Instituto Nacional de Pesquisas Espaciais (INPE)}
and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Instituto Nacional de Pesquisas Espaciais (INPE)}",
title = "Phenomenology and characterization of multiple ground contact
strokes in natural lightning",
booktitle = "Proceedings...",
year = "2014",
organization = "ICAE 2014. - International Conference on Atmospheric
Electricity.",
note = "Informa{\c{c}}{\~o}es Adicionais: An analysis of the
phenomenology and overall characteristics of 35 cloud-to-ground
(CG) strokes that create two or more contact points to the ground
in a millisecond scale are presented. This dataset includes both
the classical forked strokes (first observed in streak camera
records) and the new class of this type of phenomenon, called
upward illumination strokes, introduced in more recent works. The
broad class of strokes that present two or more contact points in
a millisecond and sub-millisecond scale was termed multi ground
contact strokes (MGCS) as their geneses are very similar: one
branch from the main trunk of a stepped leader produces a second
stroke shortly after the first return stroke occurs. Over a
five-day campaign, a total of 357 negative CG flashes were
recorded by the RAMMER network, which is comprised of four
high-speed video cameras (three stationary monochromatic and one
mobile colored). They were set up for recording with 1200 x 500
pixels per frame, at 2500 frames per second (390- s exposure
time). From careful visual inspection, 35 MGCS events were found,
among which 22 were classified as forked strokes and 13 as UI
strokes. RAW data from BrasilDAT network was used to identify and
give additional information about the MGCS. After a number of
detailed case studies and a review of the recent literature, it
was found that the main difference between UI and classical forked
stroke events are: a) UI stroke channels present an optical
discontinuity from the main trunk during its development (i.e.,
there was a region of lower or no apparent luminosity between its
brighter region and the forking point from the main channel), b)
the time between strokes is longer than in the case of classical
forked strokes and c) the peak currents of the UI strokes are,
usually, very small. Analysis of the relationship between the
interstroke interval and peak current added new information on the
physical characteristics and distinctive features of UI and
forked.",
keywords = "Forked strokes, Multiple ground contacts, Lightning Physics,
High-speed video.",
abstract = "An analysis of the phenomenology and overall characteristics of 35
cloud-to-ground (CG) strokes that create two or more contact
points to the ground in a millisecond scale are presented. This
dataset includes both the classical forked strokes (first observed
in streak camera records) and the new class of this type of
phenomenon, called upward illumination strokes, introduced in more
recent works. The broad class of strokes that present two or more
contact points in a millisecond and sub-millisecond scale was
termed multi ground contact strokes (MGCS) as their geneses are
very similar: one branch from the main trunk of a stepped leader
produces a second stroke shortly after the first return stroke
occurs. Over a five-day campaign, a total of 357 negative CG
flashes were recorded by the RAMMER network, which is comprised of
four high-speed video cameras (three stationary monochromatic and
one mobile colored). They were set up for recording with 1200 x
500 pixels per frame, at 2500 frames per second (390-µs exposure
time). From careful visual inspection, 35 MGCS events were found,
among which 22 were classified as forked strokes and 13 as UI
strokes. RAW data from BrasilDAT network was used to identify and
give additional information about the MGCS. After a number of
detailed case studies and a review of the recent literature, it
was found that the main difference between UI and classical forked
stroke events are: a) UI stroke channels present an optical
discontinuity from the main trunk during its development (i.e.,
there was a region of lower or no apparent luminosity between its
brighter region and the forking point from the main channel), b)
the time between strokes is longer than in the case of classical
forked strokes and c) the peak currents of the UI strokes are,
usually, very small. Analysis of the relationship between the
interstroke interval and peak current added new information on the
physical characteristics and distinctive features of UI and forked
strokes.",
conference-location = "Norman",
conference-year = "2014",
label = "lattes: 4161737266837399 1 CamposSaCuAnPiGu:2014:PhChMu",
language = "en",
url = "http://www.nssl.noaa.gov/users/mansell/icae2014/preprints/Campos_57.pdf",
urlaccessdate = "25 abr. 2024"
}