TAIPEI (Taiwan News) -- New Taipei City's Xindian District witnessed a "fire rainbow" yesterday morning (April 18), according to Cheng Ming-dean (鄭明典), director of the bureau's Meteorological Research and Development Center.
On his Facebook page, Cheng posted an image of what he called a "textbook" example of a "fire rainbow," or circumhorizontal arc, which he said is actually not a rainbow, but is actually a halo formed by sunlight refracting through ice crystals suspended in the atmosphere. Cheng said that it appeared in the morning over the skies of Xindian District and Facebook user Chu Hsin-chieh (褚信介) submitted the photo he took of the rare phenomenon.
The phenomenon gets its name because it appears to be a rainbow that spontaneously appears across the sky and has a red upper edge. It is only when the height of cirrus clouds reach at least 6,100 meters, there are enough ice crystals in the cloud layer and the sun shines at a 58 degree angle that a fire rainbow can appear.
"Fire rainbow." (Photo by Chu Hsin-chieh)