Scientists have pierced the veil of clouds around a volcanic plume to "see" lightning.
Click on image for full size
Image Courtesy of Bretwood Higman

Scientists Pierce Veil of Clouds to "See" Lightning Inside a Volcanic Plume
News story originally written on April 7, 2009

Researchers hit the jackpot in late March, when, for the first time, they began recording data on lightning in a volcanic eruption--right from the start of the eruption.

Using a multi-station, ground-based Lightning Mapping Array, the scientists advanced our understanding of electrical activity during a volcanic eruption.

Portable Lightning Mapping Arrays are now set up in several areas of the country, and are becoming increasingly used by meteorologists to issue weather warnings.

The arrays have been deployed at volcanoes only twice before.

Thousands of individual segments of a single lightning stroke can be mapped with the Lightning Mapping Array, and later analyzed to reveal how lightning initiates and spreads through a thunderstorm, or in a volcanic plume.

When Alaska's Redoubt Volcano started rumbling in January, a team of researchers hurried to set up a series of the arrays.

When the volcano erupted on March 22 and 23, 2009, the arrays returned dramatic information about the electricity created within volcanic plumes, and the resulting lightning.

"For the first time, we had the Lightning Mapping Array on site before the initial eruption," said scientist Sonja Behnke of New Mexico Tech.

"The data will allow us to better understand the electrical charge structure inside a volcanic plume," said scientist Ron Thomas of New Mexico Tech. "That should help us learn how the plume is becoming electrified, and how it evolves over time."

Bradley Smull, program director in the National Science Foundation (NSF)'s Division of Atmospheric Sciences, which funded the research, said the information will give scientists insights into the electrical mechanisms in both plumes above active volcanoes, and in lightning spawned in thunderstorms.

NSF awarded New Mexico Tech a grant to study volcanic lightning in 2007, with the University of Alaska at Fairbanks and the Alaska Volcano Observatory as collaborators.

"With data from the Lightning Mapping Array, new details of volcanic plume lightning will emerge," Smull said. "The opportunity for stand-alone analysis, and comparisons with last year's similar observations of Chaiten Volcano in Chile, will tell us much more about this phenomenon."

Redoubt was "a perfect laboratory," said physicist Paul Krehbiel of New Mexico Tech. "It erupted on schedule--and gave us two months' notice."

Advance warning was critical to the mission.

In late 2008, Redoubt showed initial signs of seismic activity. Volcanologist Steve McNutt and colleagues at the Alaska Volcano Observatory (AVO) started scouting locations for sensors.

Then in March, "this volcano, in the space of a week, had several major eruptions that produced prolific lightning," Krehbiel said.

The four Lightning Mapping Array stations are located along the east side of Cook Inlet, across from the volcano.

Thomas, Krehbiel, Behnke and McNutt found cooperative people in accessible locations to serve as caretakers for the stations: The northernmost sensor is at a school teacher's house in Nikiski. The second is at a fire station south of Kenai. A third is at Clam Gulch Lodge. The southernmost and fourth sensor is at a public school in Ninilchik.

In addition to the Lightning Mapping Array, the AVO is gathering data from 11 local seismic stations, two infrasound arrays and two radar stations.

"It's hard to get the sensors set up before a volcano erupts," said Thomas. "You plan--and hope you can do something like this once in a lifetime."

The Redoubt eruptions are not over yet. After quieting down and appearing to go into a dome-building phase, just before sunrise this past Saturday the volcano blew its top in the biggest eruption so far.

"The lightning  activity was as strong or stronger than we have seen in large midwestern thunderstorms," Krehbiel said. "The radio frequency noise was so strong and continuous that people living in the area would not have been able to watch broadcast VHF television stations."

Text above is courtesy of the National Science Foundation

Last modified May 19, 2009 by Becca Hatheway.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Thunder and Lightning

Lightning is the most spectacular element of a thunderstorm. In fact it is how thunderstorms got their name. Wait a minute, what does thunder have to do with lightning? Well, lightning causes thunder....more

Guide to Weather Advisories, Watches, and Warnings

A watch, warning, or advisory is an important way for the National Weather Service of the United States to alert people about hazardous weather. As a community member, it is vital to be aware of any watches,...more

Thunderstorms

Thunderstorms are one of the most thrilling and dangerous types of weather phenomena. Over 40,000 thunderstorms occur throughout the world each day. Thunderstorms form when very warm, moist air rises into...more

Plume Volcanism

The Hawaiian Islands are an example of the way some volcanoes are made. A rising hot plume of material makes it's way to the lithosphere of the Earth from the deep interior, and erupts material unto the...more

Weather Radar

Radar is important to weather forecasters because it can detect rain and hail in clouds. The radar emits radio waves in all directions. When a radio wave hits water or ice particles, some of the energy...more

Volcano Formation

Volcanoes form when hot material from below risesand leaks into the crust. This hot material, called magma, comes either from a melt of subducted crustal material, which is light and buoyant after melting,...more

Tornado-like Rotation is Key to Understanding Volcanic Plumes

A 200-year-old report by a sea captain and photographs of the 2008 eruption of Mount Chaiten are helping scientists better understand strong volcanic plumes. In a paper published this week in the journal...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA