Ulloa's ring

From Glossary of Meteorology



Ulloa's ring

(Also called Bouguer's halo.) An infrequently observed, faint white, circular arc or complete ring of light that has a radius of 39° and is centered on the antisolar point.

When observed, it is usually in the form of a separate outer ring around an anticorona.

Tricker, R. A. R. 1970. An Introduction to Meteorological Optics. 192–193.


Copyright 2024 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.