cirrus (Ci)

[氣象] 卷雲.

Deriving their name from the Latin for "a lock of curly hair," cirrus clouds are white fibrous clouds composed of ice crystals. These ice crystals may be large and may fall out of the cloud before evaporating. This fall out of ice crystals extends the cloud in the vertical. A cirrus cloud, one of the three major cloud types that comprise the ten main groups or genera, is not a cloud layer but a single cloud element.