circumhorizontal arc

Related Overviews


'circumhorizontal arc' can also refer to...


More Like This

Show all results sharing this subject:

  • Meteorology and Climatology


Show Summary Details

Quick Reference

An occasionally spectacular halo phenomenon that consists of a brilliantly coloured arc lying parallel to the horizon and sometimes extending for as much as 120°. It arises from refraction through ice-crystal faces with a 90° included angle, when light enters through a vertical face and exits from a horizontal one (compare circumzenithal arc). It may be observed only when the solar elevation exceeds 58°, and is thus most readily visible from lower latitudes. If the 46° halo is present the arc normally lies slightly below its lowest point, becoming tangential at a solar elevation of 68°.

Subjects: Meteorology and Climatology.

Reference entries

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.