A halo is an optical phenomenon produced by light interacting with ice crystals suspended in the atmosphere. In this clip by Jorge Guzman, you can see a 22° halo and a circumhorizontal arc.
A 22° halo and a circumhorizontal arc are two types of halos that are caused by the refraction of light by ice crystals in the atmosphere. They are both circular or arc-shaped optical phenomena that appear around or below the Sun or Moon. However, they have different characteristics and formation conditions.
A 22° halo is a white or colored ring that forms around the Sun or Moon at a radius of about 22 degrees. It is caused by the refraction of light by randomly oriented, hexagonal ice crystals in cirrus or cirrostratus clouds. The colors of the 22° halo are usually faint and red on the inside and blue on the outside. A 22° halo can be seen at any time of the year and at any latitude, as long as the Sun or Moon is not too high in the sky.
A circumhorizontal arc is a bright and colorful band that forms parallel to the horizon, below the Sun or Moon. It is caused by the refraction of light by plate-shaped, hexagonal ice crystals that are horizontally aligned in cirrus clouds. The colors of the circumhorizontal arc are more vivid and reversed from those of a rainbow, with red on top and violet at the bottom. A circumhorizontal arc can only be seen when the Sun or Moon is very high in the sky, at an elevation of 58 degrees or greater. This means that it is more common in tropical and subtropical regions, and rare or impossible in higher latitudes.
In summary, a 22° halo and a circumhorizontal arc are both halos, but they differ in their shape, color, and occurrence. A 22° halo is a ring around the Sun or Moon, with faint colors and red on the inside. A circumhorizontal arc is a band below the Sun or Moon, with bright colors and red on top. A 22° halo can be seen at any time and place, while a circumhorizontal arc can only be seen when the Sun or Moon is very high in certain regions. I hope this explanation helps you understand these beautiful phenomena better. 😊🙏
