Sprite (lightning)
Sprites or red sprites are large-scale
Precis
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First color image of a sprite, taken from an aircraft
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A sprite over Laos, as seen from the International Space Station
Sprites appear as luminous red-orange flashes. They often occur in clusters above the troposphere at an altitude range of 50–90 km (31–56 mi). Sporadic visual reports of sprites go back at least to 1886.[1] They were first photographed on July 4, 1989,[2] by scientists from the University of Minnesota and have subsequently been captured in video recordings thousands of times.
Sprites are sometimes inaccurately called
History
The earliest known report is by Toynbee and Mackenzie in 1886.[3] Nobel laureate C. T. R. Wilson had suggested in 1925, on theoretical grounds, that electrical breakdown could occur in the upper atmosphere, and in 1956 he witnessed what possibly could have been a sprite. They were first documented photographically on July 6, 1989, when scientists from the University of Minnesota, using a low-light video camera, accidentally captured the first image of what would subsequently become known as a sprite.[4]
Several years after their discovery they were named
In 2016, sprites were observed during Hurricane Matthew's passage through the Caribbean.[7] The role of sprites in the tropical cyclones is presently unknown.[8]
Characteristics
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Different types of electrical phenomena in the atmosphere
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A sprite seen from the International Space Station (top right, faint red above the lightning).
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ISS sprite image above; zoomed in
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Another shot from the first color clip of the sprite.
Sprites have been observed over North America,[9] Central America, South America,[10] Europe,[11] Central Africa (Zaire), Australia, the Sea of Japan and Asia and are believed to occur during most large thunderstorm systems.
Rodger (1999) categorized three types of sprites based on their visual appearance.[1]
- Jellyfish sprite – very large, up to 50 by 50 km (31 by 31 mi).
- Column sprite (C-sprite) – large-scale electrical discharges above the earth that are still not totally understood.
- Carrot sprite – a column sprite with long tendrils.
Sprites are colored reddish-orange[5] in their upper regions, with bluish hanging tendrils below, and can be preceded by a reddish halo. They last longer than normal lower stratospheric discharges, which last typically a few milliseconds, and are usually triggered by the discharges of positive lightning between the thundercloud and the ground,[12] although sprites generated by negative ground flashes have also been observed.[13] They often occur in clusters of two or more, and typically span the altitude range 50 to 90 kilometres (31 to 56 mi), with what appear to be tendrils hanging below, and branches reaching above.[5]
Optical imaging using a 10,000 frame-per-second
In order to film sprites from Earth, special conditions must be present: 150–500 km (93–311 mi) of clear view to a powerful thunderstorm with positive lightning between cloud and ground, red-sensitive recording equipment, and a black unlit sky.[15]
Mechanism
Sprites occur near the top of the mesosphere at about 80 km altitude in response to the electric field generated by lightning flashes in underlying thunderstorms. When a sufficiently large positive lightning strike carries charges to the ground, the cloud top is left with a strongly negative net charge. This can be modeled as a quasi-static electric dipole and for less than 10 milliseconds a strong electric field is generated in the region above the thunderstorm. In the low pressure of the upper mesosphere the breakdown voltage is drastically reduced, allowing for an electron avalanche to occur.[16][17] Sprites get their characteristic red color from excitation of nitrogen in the low pressure environment of the upper mesosphere. At such low pressures quenching by atomic oxygen is much faster than that of nitrogen, allowing for nitrogen emissions to dominate despite no difference in composition.[18][19]
Sprite halo
Sprites are sometimes preceded, by about 1 millisecond, by a sprite
Research carried out at Stanford University in 2000 indicates that, unlike sprites with bright vertical columnar structure, occurrence of sprite halos is not unusual in association with normal (negative) lightning discharges.[22] Research in 2004 by scientists from Tohoku University found that very low frequency emissions occur at the same time as the sprite, indicating that a discharge within the cloud may generate the sprites.[23]
Related aircraft damage
Sprites have been blamed for otherwise unexplained accidents involving high altitude vehicular operations above thunderstorms. One example of this is the malfunction of a NASA stratospheric balloon launched on June 6, 1989, from Palestine, Texas. The balloon suffered an uncommanded payload release while flying at 120,000 feet (37,000 m) over a thunderstorm near Graham, Texas. Months after the accident, an investigation concluded that a "bolt of lightning" traveling upward from the clouds provoked the incident.[24] The attribution of the accident to a sprite was made retroactively, since this term was not coined until late 1993.
See also
- Upper-atmospheric lightning (includes Blue Jets)
- Aurora (astronomy)
- Catatumbo lightning
- Cosmic ray visual phenomena
References
- ^ .
- ^ "NASA - Heliophysics Nugget: Seeing Sprites".
- S2CID 4128139.
- S2CID 9343018.
- ^ .
- ^ "Sprite Lightning at 100,000 Frames Per Second". APOD.NASA.gov. NASA's APOD (Astronomy Picture of the Day blog). Retrieved 19 July 2022.
- ^ "Rare, Colorful Lightning Sprites Dance Over Hurricane Matthew". National Geographic. October 3, 2016. Archived from the original on October 4, 2016. Retrieved October 3, 2016.
- ^ "Hurricane Matthew and the Day/Night Band". Cooperative Institute for Meteorological Satellite Studies. University of Wisconsin–Madison. October 7, 2016. Retrieved November 3, 2016.
- ^ Kathy Berry (1994). Spectacular Color Flashes Recorded Above Electrical Storms. NASA. Retrieved on 2009-02-18.
- ^ Don Savage and Kathy Berry (1995). Sprites Confirmed Over Storms Outside U.S. For First Time. NASA. Retrieved on 2009-02-18.
- ^ "Rare Atmospheric Phenomenon Observed from Armagh". Archived from the original on 2013-09-05. Retrieved 2013-08-21.
- S2CID 8840716.
- .
- . L11105.
- ^ Grønne, Jesper. "Første danske 'red sprites' fanget fra Silkeborg" Archived August 22, 2012, at the Wayback Machine Danish Meteorological Institute, 20 August 2012. Retrieved: 20 August 2012.
- ISSN 1520-0493.
- ISSN 0148-0227.
- ISSN 0148-0227.
- ISSN 0094-8276.
- ^ Rina Miyasato, Hiroshi Fukunishi, Yukihiro Takahashi, Michael J. Taylor, Hans. C. Stenbaek-Nielsen (2002). Characteristics of Lightning-induced Sprite Halos and Their Generation Mechanisms. Academic Society Home Village. Retrieved on 2009-02-18. [dead link]
- ^ Christopher Barrington Leigh (2000). Sprite halos. Archived 2008-09-17 at the Wayback Machine Stanford University. Retrieved on 2008-02-18.
- ^ a b Barrington-Leigh, C. P., U. S. Inan, and M. Stanley, "Identification of Sprites and Elves with Intensified Video and Broadband Array Photometry", J. Geophys. Res. 106, No. 2, February, 2001.
- S2CID 53059204.
- ^ STRATOCAT (2009). "Data of the stratospheric balloon launched on 6/5/1989 from Columbia Scientific Balloon Facility, Palestine, Texas, US for Molecules observation made fluorescent with a Laser". Retrieved 2009-02-18.
External links
- "Red Sprites & Blue Jets" – a digital capture of the VHS video distributed in 1994 by the University of Alaska Fairbanks that popularized the terms
- "Red Sprites and Blue Jets". Archived from the original on 2002-09-14. Retrieved 2012-08-20. – webpage by University of Alaska Fairbanks
- Ground and Balloon-Borne Observations of Sprites and Jets
- Darwin Sprites '97 Space Physics Group, University of Otago
- Sprites, jets and TLE pictures and articles
- Sprites in Europe: European contributors blog
- Kanmae, T.; Stenbaek-Nielsen, H.C.; McHarg, M.G.; Haaland, R.K. (2010). "Observation of blue sprite spectra at 10,000 fps". Geophys. Res. Lett. 37 (13): L13808. .
- "Mysterious Sprite Photographed by ISS Astronaut: Big Pic". Archived from the original on 2012-07-14. Retrieved 2012-07-13.
{{cite web}}
: CS1 maint: bot: original URL status unknown (link) - Short professional bio of Dr 'Geoff' McHarg
- Photography website Petapixel posted a link to a very rare and very clear photograph of a sprite taken by photographer Mike Hollingshead. Article at Photographer Captures Rare Photograph of a Sprite with an Aurora
- At the Edge of Space – a NOVAprogram that examines the phenomenon of Sprites
- Red Sprites Over Adriatic Sea Seen from the Czech Republic (14 January 2019)