Blue Jet Lightning sparks an unusual type of lightning in the upper atmosphere
Scientists have finally gotten a good picture of the spark that sets off an exotic form of lightning. From thunderclouds, blue jet lightning zips upwards into the stratosphere, reaching altitudes up to around 50 kilometers in less than a second. Although ordinary lightning excites a medley of gases in the lower atmosphere to glow white, to produce their characteristic blue hue, blue jets excite mainly stratospheric nitrogen.
Blue jet lightning has been observed from the ground and aircraft for many years, but without getting high above the clouds, it’s difficult to tell how they shape. Now, researchers say in a recent online article on January 20 in Nature.com, instruments on the International Space Station have spotted a blue jet emerging from an extremely brief, bright burst of electricity near the top of a thundercloud.
It is vital to understand blue jet lightning and other thunderstorm-related upper-atmosphere phenomena, such as sprites (SN: 6/14/02) and elves (SN: 12/23/95), since these events can influence how radio waves move through the air, potentially impacting communication technologies, says Victor Pasko, a Penn State space physicist who was not involved in the work.
The blue jet was observed in February 2019 in a storm over the Pacific Ocean, near the island of Nauru, by cameras and light-sensing instruments called photometers on the space station. “It all starts with what I think of as a blue bang,” says Torsten Neubert, an atmospheric physicist at the Kongens Lyngby Technical University of Denmark.
The ‘blue bang’ was a burst of 10 microseconds of bright blue light, about 16 kilometers high, near the top of the cloud. A blue jet shot up into the stratosphere from that flashpoint, rising as high as about 52 kilometers over several hundred milliseconds.