Weather: an iridescent cloud seen in Asia

A multicolored halo hung in the sky of southern China. This strangeness is not usual and the image surprised. The name given to this phenomenon is “iridescent cloud”. It has the particularity of encompassing the colors of the rainbow. To obtain such a spectacle, several elements are essential. Thus, the cloud must be thin. Then, sunlight must penetrate the cloud at an angle of 10 to 40°C. It is thanks to this that the diffraction of light will be created and may give rise to this phenomenon.

However, this type of cloud is very rare. “In general, when we observe them, it is quite high on the horizon and it is rather at the beginning or at the end of the day, when the relative position of the sun, the cloud and the observer allows it”describes Samuel Morin, researcher at Météo France and CNRS. This kind of clouds was created most of the time in Asia, because the climate is favorable there. One of them was seen in Japan in the summer of 2022. Also, an iridescent cloud was seen in Gavarnie (Hautes-Pyrenees) in France.