Sprites, Blue Jets, and Elves

1. Sprites, Blue Jets, and Elves What’s On the Other Side of the Storm

2. What Are They? • Sprites, Blue Jets and Elves are upper-atmospheric lightning recently discovered in 1995. • They are formed when the electric field of thunderstorms generates ambient electrons, causing them to impact one another and create optical emissions only visible from 100s of miles away.

3. Where They Form

4. Sprites • These form at ~70km altitude and move both upward and downward from their origination point. • Sprites usually occur during the dying stages of a thunderstorm, and are frequent with large cloud-to-ground lightning strikes. • Although Sprites have a weak electromagnetic emission, they can reach up to 100km tall, sometimes breaking the ozone barrier.

5. Blue Jets • Blue Jets do not occur because of cloud-to-ground lightning, but interestingly are frequent during hail storms. • They reach ~35km altitude with an upward velocity of 112km/s (Geophysical Institute, Heavener, Moudry, Sentman and Wescott). • It is argued that because of its intense velocity, blue jets emanate from the center of thunderstorms, but this claim is widely disputed (Science and Technology News).

6. Larger View of Blue Jet

7. Elves • E.l.v.e.s stands for Emissions of Light and VLF perturbations due to EMP Sources (Fukunishi et al., 1995). • These generally occur above thunderstorms, both in conjunction with sprites and alone. • At an altitude of 75-95km, they are located higher than sprites, and can span horizontally as much as 530km (Heavener, Matthew 2000)

8. What’s the Big Deal? • I had two main questions: • How much electromagnetic energy do these forms of lightning put out? • Does the electromagnetic energy have any effect on the ozone layer, and if so, what does that mean for global warming?

9. On thewhole,red spectral observations (sprites) showed an emission of 550-850 nm. Blue Jets were stronger, emitting anywhere from 700-1000 nm, showing a higher energy process was at stake. (Heavener, Matthew 2000) Circular Elves are so short lived that they are deemed less important energetically that sprites and jets (aww). Sprite, Blue Jet and Elves Electromagnetic Emissions

10. So, What About Global Warming and the Ozone?

11. Whaa, wha, whaaaaaa! • Actually, the technical explanation gets into some atmospheric chemistry models, none of which I am familiar with… • But, I can say that the amount of electromagnetic energy put out by these 3 millisecond bursts are not enough to battle the sun once it comes up. • However, since this is a new field of study for chemists and meteorologists alike, these tiny changes in the climate system’s initial conditions might add up to a problem in the long run, especially if global warming increases the incidences of strong electrical storms, thus create more sprites, blue jets, and elves.

12. My Conclusion: They ROCK!

14. Sources • Amato, Ivan. “Sprites Trigger Sky-High Chemistry.”Chemical and Engineering News. 20 Mar, 2006. Vol 84. • Barrington-Leigh, C.P., Bell, T.F.,Cummer, S.A., Inan, U.S. “Elf Radiation Produced by Electrical Currents in Sprites.”Space, Telecommunications and Radioscience Laboratory, Stanford University. Stanford, CA. Geophysical Research Letters,15 Apr 1998. Vol 25, No. 8 • Heavener, Matthew J., Moudry, Dana R., Sentman, Davis D., Wescott, Eugene M. “Sprites, Blue Jets, and Elves: Optical Evidence of Energy Transport Across the Stratopause.” Geophysical Institute, University of Alaska Fairbanks. 19 Sept, 1999. Vol 5.