Superbolts, the strongest lightning bolts, occur at surprising times and in surprising places, a new study has found.
Scientists define superbolts as lightning bolts a thousand times stronger than average. And while you may associate the strongest thunderstorms with summertime near a coast, an analysis of lightning data found that superbolts are most likely to occur from November to February on the open ocean, far from the places where lightning occurs most often.
The researchers analysed 2 billion lightning strikes that were recorded from 2010 to 2018 by the global sensor network called the World Wide Lightning Location Network (of which the study’s first author, the University of Washington’s Robert Holzworth, is the director). The network of sensors waits for the electromagnetic radiation from lightning, and uses at least five of the 80+ stations to find where and when the bolt hit.
The researchers picked out the bolts that were a thousand times more energetic than the average lightning strike for this analysis, carefully weeding out any potential erroneous data. Compared to regular lightning, superbolts showed some unexpected patterns.
They already knew that lightning is 10 times more likely to strike land than water and is typically concentrated over “three chimneys,” located in tropical and subtropical Americas and Africa plus the southeast Asian island nations. But none of these areas had many superbolts, according to the paper published in Journal of Geophysical Research: Atmospheres.
Instead, superbolts mostly occurred over the Eastern North Atlantic, the Mediterranean, and the Andes, with regions of strong activity in and around Japan and along the equator in the Atlantic and Indian oceans.
The researchers cited evidence that, for some reason, the ocean seems to enhance lightning bolts’ energy. Why, they don’t know — but maybe more studies of these superbolts will help out.
Despite its ubiquity, lightning remains a perplexing topic with various potential drivers that sometimes shows strange radioactive properties. And it’s cool that something so common can still be so fascinating.