2020 volcanic eruption leads to hours-long thunderstorm
Date:
January 19, 2022
Source:
Geological Society of America
Summary:
A study discusses how advances in global lightning detection have
provided novel ways to characterize explosive volcanism.
FULL STORY ==========================================================================
A study conducted by scientists at the U.S. Geological Survey, the
National Oceanic and Atmospheric Administration, and Vaisala Inc.,
published yesterday in the Geological Society of America's journal
Geology, discusses how advances in global lightning detection have
provided novel ways to characterize explosive volcanism. Lead author
Alexa Van Eaton says, "It's the perfect storm -- explosive eruptions
can create lightning that is detected around the world."
==========================================================================
The January 2020 eruption of Taal volcano in the Philippines showed how
a powerful volcanic eruption becomes electrified, giving off thousands
of cloud- to-ground lightning strikes over several hours. Those flashes
allow scientists to shed light on the eruption's behavior. "As soon
as the volcanic ash plume rose high enough to freeze, its electrical
activity lit up our sensors," says Van Eaton.
Radio waves produced by lightning travel at the speed of light, so,
unlike other remote sensing tools with longer lag times, "we can receive
the lightning data super-fast," explains Van Eaton. The scientists also
used satellite images and hundreds of photos shared on social media. "The eruption took place in a major urban area, so people posted pictures of volcanic lightning as it was happening." Those photos and videos, Van
Eaton and colleagues write, "reveal a highly electrified region at the
base of the umbrella cloud." "Much more can be done to characterize an eruption when there are camera perspectives from all angles," says Van
Eaton. And understanding the evolution of volcanic lightning helps us
recognize the early warning signs of ash hazards to aircraft." However, remote-sensing studies like this one "only provide a broad-brush picture
of an eruption," says Van Eaton. "It is clear that nothing can replace the
work of local geologists who know the area like the backs of their hands."
An area of interest for future study, notes Van Eaton, is the miniature
sparks they observed in photos of the ash plume. "We were surprised to
find the high- altitude umbrella cloud crawling with these tiny, blue streamers," which are distinct from lightning because they are discharges
of cold plasma, rather than hot. "It's still an enigma how these little
ribbons of ionized air relate to powerful lightning." Note: On Sat., 15
Jan. 2022, a massive volcanic eruption from the submarine volcano in Tonga known as Hunga Tonga-Hunga Ha'apai occurred. It sent a tsunami across
the entire Pacific Ocean while a giant ash cloud spread out overhead,
producing record-breaking amounts of volcanic lightning. Van Eaton and colleagues' Geology paper explains how such water-rich volcanic plumes
become electrically charged.
========================================================================== Story Source: Materials provided by Geological_Society_of_America. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Alexa R. Van Eaton, Cassandra M. Smith, Michael Pavolonis,
Ryan Said.
Eruption dynamics leading to a volcanic thunderstorm--The January
2020 eruption of Taal volcano, Philippines. Geology, 2022; DOI:
10.1130/ G49490.1 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/01/220119135034.htm
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