Nov 8, 2023
Not all lightning bolts are created equal.
The average strike measures at about 300 million volts of electrical energy. That’s more than 300,000 times the amount needed to power a house’s lights. But about 1% of lightning bolts are much stronger. They can burst at up to 300 billion volts. The origins of these “superbolts” had baffled scientists for years. Now, a team of researchers at the Hebrew University of Jerusalem believes they’ve solved the mystery. They published their findings last month in the Journal of Geophysical Research: Atmospheres.
Avichay Efraim is the study’s lead author. Efraim told Phys.org: "Superbolts, even though they're only a (very small fraction) of all lightning, they're a magnificent phenomenon."
Efraim’s team focused on the three regions of the planet where superbolts have been most often observed: the northeast Atlantic Ocean, the Mediterranean Sea, and the Altiplano plateau of Bolivia and Peru.
"We wanted to know what makes these powerful superbolts more likely to form in some places as opposed to others," Efraim said.
The team reviewed 10 years’ worth of observed lightning data in the three regions. They assessed many factors. Bolt strength was one. Air temperatures, cloud types, and air quality were others. Their conclusion? Height matters.
“Our results show that the energy per stroke (rises) sharply as the distance between the cloud's charging zone and the surface decreases,” Efraim wrote. In other words, the closer the storm cloud to the surface, the stronger the lightning bolt.
Charged with their new findings, Efraim’s team has a new aim. They want to observe how climate change may affect superbolts.
Photo from Unsplash courtesy of Micah Tindell.
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