circumhorizontal arc

cir·​cum·​horizontal arc

Definition of circumhorizontal arc

: a colored halo of 90° extent or less that is red on the upper side, parallel to the horizon and 46° or a little more below the sun, and produced by the refraction of light across 90° angles at the undersides of ice crystals in suspension in the air

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Cite this Entry

“Circumhorizontal arc.” Dictionary, Merriam-Webster, Accessed 23 Jan. 2021.

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