Circumzenithal arc
Videos
The circumzenithal arc, also called the circumzenith arc, the upside-down rainbow, and the Bravais arc, is an optical phenomenon similar in appearance to a rainbow, but belonging to the family of halo
A circumzenithal arc in Salem, Massachusetts, Oct 27, 2012. Also visible are a supralateral arc, Parry arc (upper suncave), and upper tangent arc.
From top to bottom: a circumzenithal arc on top of a 46° halo, on top of a Parry arc, on top of a tangent arc, on top of a 22° halo, on top of the actual sun.
A Circumzenithal Arc. Seen in Mount Vernon, Washington. : June 10, 2024
Tangent arc
Videos
Tangent arcs are a type of halo, an atmospheric optical phenomenon, which appears above and below the observed Sun or Moon, tangent to the 22° halo. To produce these arcs, rod-shaped hexagonal ice cry
An upper tangent arc appearing above San Francisco Bay and Marin County in California, at sunset on April 9, 2023.
An upper tangent arc with the Sun at an observed low altitude.
A halo display observed over the South Pole. Featured in the photo are several distinct phenomena: A parhelic circle (horizontal line), a 22° halo (circle) with a sundog (bright spot), and an upper tangent arc. Photo: Cindy McFee, NOAA, December 1980.
A 22° halo featuring two sun dogs on both sides, as well as an upper and a lower tangent arcs at the top and the bottom.