@Article{PoelmanSPHSHSVMSW:2021:GlGrSt,
author = "Poelman, Dieter R. and Schulz, Wolfgang and Pedeboy, Stephanie and
Hill, Dustin and Saba, Marcelo Magalh{\~a}es Fares and Hunt, Hugh
and Schwalt, Lukas and Vergeiner, Christian and Mata, Carlos T.
and Schumann, Carina and Warner, Tom",
affiliation = "{Royal Meteorological Institute of Belgium} and {Austrian
Lightning Detection and Information System (ALDIS)} and
{M{'e}t{'e}orage} and {Scientific Lightning Solutions LLC (SLS)}
and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{University of Witwatersrand} and {Graz University of Technology}
and {Graz University of Technology} and {Scientific Lightning
Solutions LLC (SLS)} and {University of Witwatersrand} and {ZT
Research}",
title = "Global ground strike point characteristics in negative downward
lightning flashes-Part 1: Observations",
journal = "Natural Hazards and Earth System Sciences",
year = "2021",
volume = "21",
number = "6",
pages = "1909--1919",
month = "June",
abstract = "Information about lightning properties is important in order to
advance the current understanding of lightning, whereby the
characteristics of ground strike points (GSPs) are in particular
helpful to improving the risk estimation for lightning protection.
Lightning properties of a total of 1174 negative downward
lightning flashes are analyzed. The high-speed video recordings
are taken in different regions, including Austria, Brazil, South
Africa and the USA, and are analyzed in terms of flash
multiplicity, duration, interstroke intervals and ground strike
point properties. According to our knowledge this is the first
simultaneous analysis of GSP properties in different regions of
the world applying a common methodology. Although the results vary
among the data sets, the analysis reveals that a third of the
flashes are single-stroke events, while the overall mean number of
strokes per flash equals 3.67. From the video imagery an average
of 1.56 GSPs per flash is derived, with about 60% of the
multiple-stroke flashes striking the ground in more than one
place. It follows that a ground contact point is struck 2.35 times
on average. Multiple-stroke flashes last on average 371ms, whereas
the geometric mean (GM) interstroke interval value preceding
strokes producing a new GSP is about 18% greater than the GM value
preceding subsequent strokes following a pre-existing lightning
channel. In addition, a positive correlation between the duration
and multiplicity of the flash is presented. The characteristics of
the subset of flashes exhibiting multiple GSPs is further
examined. It follows that strokes with a stroke order of 2 create
a new GSP in 60% of the cases, while this percentage quickly drops
for higher-order strokes. Further, the possibility of forming a
new lightning channel to ground in terms of the number of strokes
that conditioned the previous lightning channel shows that
approximately 88% developed after the occurrence of only one
stroke. Investigating the time intervals in the other 12% of the
cases when two or more strokes re-used the previous lightning
channel showed that the average interstroke time interval
preceding a new lightning channel is found to be more than twice
the time difference between strokes that follow the previous
lightning channel.",
doi = "10.5194/nhess-21-1909-2021",
url = "http://dx.doi.org/10.5194/nhess-21-1909-2021",
issn = "1684-9981",
language = "en",
targetfile = "poelman_global1.pdf",
urlaccessdate = "20 maio 2024"
}