Study unravels mystery of ‘gigantic jet’ lightning bursts that rise miles into space

Scientists suspect weather phenomenon may have an impact on operation of satellites in low-earth orbit

Scientists studying a thunderstorm in Oklahoma found that its electrical discharge was 100 times as powerful as that from a typical lightning bolt, an advance that sheds more light on this rare atmospheric phenomenon.

Researchers, including those from Georgia Institute of Technology in the US, say on rare occasions, lightning exits the top of a thunderstorm and connects to the lower edge of space, forming what is called a “gigantic jet”.

In the new study, published last week in the journal Science Advances, they report observations of a gigantic jet, which are a class of mysterious transient weather events, that transferred an “extraordinary amount of charge” stretching nearly 50 miles (80km) towards space.

While typical lightning bolts carry less than five coulombs of charge between the cloud and ground, or within clouds, the observed gigantic jet moved an estimated 300 coulombs of electrical charge into the ionosphere – the lower edge of space – from the thunderstorm.

“They propagate all the way to the lower ionosphere to an altitude of 50-60 miles, making a direct electrical connection between the cloud top and the lower ionosphere, which is the lower edge of space,” study corresponding author Levi Boggs from the Georgia Tech Research Institute, said in a statement.

The discharge, according to the study, included streamers of plasma – the fourth state of matter – as well as extremely hot structures (4400°C) called leaders.

Gigantic jets, scientists suspect, may also have an impact on the operation of satellites in low-earth orbit.

However, they say observations of such gigantic jets are rare and happen by chance – “from pilots or aircraft passengers happening to see them or ground observers operating night-scanning cameras”.

Researchers suspect the frequency of gigantic jets range from 1,000 per year up to 50,000 per year, reported more often in tropical regions of the world.

In the new study, researchers say they learned about the Oklahoma event from a colleague who told them about a gigantic jet photographed by a citizen-scientist with a low-light camera in operation on 14 May 2018.

This weather event was found to have taken place in a location with a nearby lightning mapping system, within range of two Next Generation Weather Radar locations, and also accessible to instruments on satellites from the US National Oceanic and Atmospheric Administration.

“We were able to see very high frequency sources above the cloud top, which had not been seen before with this level of detail,” Dr Boggs said.

“Using satellite and radar data, we were able to learn where the very hot leader portion of the discharge was located above the cloud,” he added.

Researchers say “this is probably the first time” the structure elements of a gigantic jet has been three-dimensionally mapped above the clouds.

While the elusive weather phenomenon has been observed and studied over the past two decades, scientists say detections are still rare since there are no specific observing systems to look for them.