Elusive Blue Jets and Red Sprites appeared over a lightning storm in the sky of Bali, Indonesia on March 19, 2016.
To me, this is the first time both of these unrelated transient luminous events have been caught at the same time over a thunderstorm. Wow!
Red sprites and blue jets are upper atmospheric optical phenomena associated with thunderstorms.
The first images of a sprite were accidently obtained in 1989. Beginning in 1990, about twenty images have been obtained from the space shuttle.
Numerous images have also been obtained from aircraft of blue jets, also a previously unrecorded form of optical activity above thunderstorms. Blue jets appear to emerge directly from the tops of clouds and shoot upward in narrow cones through the stratosphere. Their upward speed has been measured to be about 100 km per second.
Anecdotal reports of “rocket-like” and other optical emissions above thunderstorms go back more than a century, and there have been several pilot reports of similar phenomena.
Together, these phenomena suggest that thunderstorms exert a much greater influence on the middle and upper atmospheres than was previously suspected.
Sprites are massive but weak luminous flashes that appear directly above an active thunderstorm system and are coincident with cloud-to-ground or intracloud lightning strokes. Sprites are predominantly red. The brightest region lies in the altitude range 65-75 km, above which there is often a faint red glow or wispy structure that extends to about 90 km. Sprites rarely appear singly, usually occurring in clusters of two, three or more.
High speed photometer measurements show that the duration of sprites is only a few ms. Current evidence strongly suggests that sprites preferentially occur in decaying portions of thunderstorms and are correlated with large positive cloud-to-ground lightning strokes.
Blue jets are a second high altitude optical phenomenon, distinct from sprites, observed above thunderstorms using low light television systems. As their name implies, blue jets are optical ejections from the top of the electrically active core regions of thunderstorms. Following their emergence from the top of the thundercloud, they typically propagate upward in narrow cones of about 15 degrees full width at vertical speeds of roughly 100 km/s (Mach 300), fanning out and disappearing at heights of about 40-50 km.
From what is known to date, it may be speculated that sprites or jets, or both, are an integral feature of every thunderstorm system of moderate size or larger in the terrestrial system, and may be an essential element of the earth’s global electrical circuit. Further, it seems likely that they have been a part of thunderstorms that have occurred over previous millions of years or longer. One may speculate about the possible occurrences of similar phenomena associated with lightning on other planets where lightning has been detected, most notably Jupiter and Venus.