circumzenithal arc


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circumzenithal arc

[¦sər·kəm¦zē·nə·thəl ′ärk]
(optics)
A brilliant rainbow-colored arc of about a quarter of a circle with its center at the zenith and about 46° above the sun, produced by refraction and dispersion of the sun's light striking the top of prismatic ice crystals in the atmosphere, and usually lasting only a few minutes.
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References in periodicals archive ?
This leads me to believe that it is indeed a circumzenithal arc captured in the image, an optical effect formed as light refracts off ice particles in thin cloud at high levels.
He was witnessing a circumzenithal arc, a beautiful and rare atmospheric phenomenon.
The phenomenon, called a circumzenithal arc, is rarely seen outside polar regions and hardly ever spotted in the UK.