Live Science is reporting that “for the first time, scientists have been able to “see” and trace lightning inside a plume of ash spewing from an actively erupting volcano.
When Alaska’s Mount Redoubt volcano began rumbling back to life in January, a team of researchers scrambled to set up a system called a Lightning Mapping Array that would be able to peer through the dust and gas of any eruption that occurred to the lightning storm happening within. Lightning is known to flash in the tumultuous clouds belched out during volcanic eruptions.
The lightning produced when Redoubt finally erupted on March 22 was “prolific,” said physicist Paul Krehbiel of New Mexico Tech. Check out the image.
“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.”
Lightning mapping arrays are increasingly being used by meteorologists to issue weather warnings, but have only been deployed at volcanoes twice before.
Thousands of individual segments of a single lightning stroke can be mapped with these arrays, and later analyzed to reveal how lightning initiates and spreads through a thunderstorm, or in a volcanic plume.
After setting up the arrays, researchers waited nearly two months for Redoubt’s first eruption, but the wait was worth it. ”
Saturday, November 21, 2009