Chugoku Shinbun reports that a halo was observed around the sun over Hiroshima yesterday.
The halo effect, called higasa [日暈] or ‘sun umbrella’ in Japanese, was observed mid-morning and, according to the newspaper, a ring of light colored red, yellow, blue and other colors hung in the sky above the cenotaph in Peace Memorial Park.
The local paper quotes a 10 year old girl from Itsukaichi as saying, “It’s the first time I’ve ever seen it. It looks like a donut”.
They are produced by the ice crystals in cirrostratus clouds high (5–10 km, or 3–6 miles) in the upper troposphere. The particular shape and orientation of the crystals is responsible for the type of halo observed. Light is reflected and refracted by the ice crystals and may split up into colors because of dispersion. The crystals behave like prisms and mirrors, refracting and reflecting sunlight between their faces, sending shafts of light in particular directions.
There is apparently an old saying “taiyo ga kasa o kaburu to ame ga furu” (when the sun has its umbrella up, rain is on its way), but lucky for us we are enjoying a beautiful, warm spring day today.