I got involved in sprites because one of my graduate committee members is organizing these campaigns and needed some extra help. I’m primarily an aurora researcher, that’s what I’m doing my thesis on at UAF. What’s your scientific background? And how did you get interested in sprites? Most large thunderstorms seem to produce the conditions that lead to sprites, but some more than others. We just look for a storm with a history of lots of large positive charge-moment-change and go look at it. So we look for a large positive charge-moment-change, which is basically the positive strokes weighted by how much charge was moved. More than just a positive stroke, the more charge that was moved during the stroke, the better the chances for a sprite. They’re associated with positive lightning strokes, which is when the cloud has a buildup of positive charge and releases a bolt of lightning. Negative strokes, from a buildup of negative charge, are about 10 times more common, so sprites aren’t strongly associated with the most common kind of lightning, but it’s not really that uncommon either. Image courtesy of Jason Ahrns via Flickr. A lightning bolt might stretch around 10 kilometers from the cloud to the ground, but a sprite can reach 50 kilometers tall.Ī “jellyfish” sprite captured over Republic County, Kansas, on August 3, 2013. They obviously beg comparison to the regular lightning bolts we see all the time, but I like to point out that the sprites are much higher, with the tops reaching up to around 100 kilometers, and higher. A large electric field, generated by some lightning strokes, ionizes the air high above the cloud, which then emits the light we see in the pictures. What’s it like to capture images of some of nature’s most short-lived and erratic features? I questioned Ahrns over email, and he explained what sprites are, why they occur, how scientists find them and why he’s so interested in the elusive phenomena.Ī sprite is a kind of upper atmosphere electrical discharge associated with thunderstorms. The researchers hope to learn more about the physical and chemical processes that give rise to sprites and other forms of upper atmospheric lightning. Ahrns and his colleagues, however, have captured extremely rare photographs of the red lightning, using DSLR cameras and high speed video cameras positioned in the plane’s window. Sprites, also known as red lightning, are electrical discharges that appear as bursts of red light above clouds during thunderstorms.Because the weather phenomenon is so fleeting (sprites flash for just milliseconds) and for the most part not visible from the ground, they are difficult to observe and even more difficult to photograph, rather like the mischievous air spirits of the fantasy realm that they’re named for. This summer, the group has taken to the skies in the National Center for Atmospheric Research’s Gulfstream V research aircraft, logging a total of 30 hours over multiple flights, in search of sprites. Air Force Academy and Fort Lewis College-all part of a project sponsored by the National Science Foundation-have been on a mission. Jason Ahrns, a graduate student at the University of Alaska-Fairbanks, and other scientists from the U.S.
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