Lightning 'superbolts' have a unique formation mechanism, satellite studies suggest - physicsworld.com

Superbolts – the rare and most extreme form of lightning — can be more than a thousand times brighter than regular lightning flashes and have a distinct formation mechanism – according to a new study done in the US.

In two new studies done at Los Alamos, Peterson, Erin Lay and Matt Kirkland analysed data collected by optical sensors aboard the Fast On-Orbit Detection of Transient Events (FORTE) and GOES-16 satellites to determine the brightness of superbolt events.

FORTE provided twelve years of lightning observations, while two years of data gathered by the Geostationary Lightning Mapper (GLM) aboard GOES-16 were analysed.

The GLM recorded 2,021,554 superbolt events with a magnitude of at least 100 times that of the average for regular lightning, while FORTE detected 20,283.

The team determined that the brightest superbolt events typically arise from rarer positively charged cloud-to-ground flashes, rather than the negatively charged phenomena that characterize most lightning.

This is unlike regular lightning, which originates in the main, negatively charged region in the mid-levels of thunderstorms – and thus carries a net negative charge to the ground.

These networks move larger amounts of charge than normal and have more compact, lightning bolts.

“The launch of the Meteosat Third Generation satellite next year will be an important milestone for space-based lightning research because it will cover a key hotspot region for lightning activity – the Congo Basin in Africa – and also a critical hotspot region for superbolts – the Mediterranean Sea.”