BBC wrote:Twelve "new" types of cloud - including the rare, wave-like asperitas cloud - have been recognised for the first time by the International Cloud Atlas.
The atlas, which dates back to the 19th Century, is the global reference book for observing and identifying clouds.
Last revised in 1987, its new fully-digital edition includes the asperitas after campaigns by citizen scientists.
Other new entries include the roll-like volutus, and contrails, clouds formed from the vapour trail of aeroplanes.
International Cloud Atlas