(Previously called castellatus.) A cloud species
of which at least a fraction of its upper part presents some vertically developed cumuliform
protuberances (some of which are taller than they are wide) that give the cloud
a crenellated or turreted appearance.
This castellanus character is especially evident when the cloud is seen from the side. The cumuliform cloud elements generally have a common base and usually seem to be arranged in lines. The species is found only in the genera cirrus
, and stratocumulus
. Cirrus castellanus differs from cirrocumulus castellanus in that its vertical protuberances subtend an angle of more than 1° when observed at an angle of more than 30° above the horizon
. When altocumulus castellanus and stratocumulus castellanus attain a considerable vertical development, they become cumulus congestus
and often develop into cumulonimbus
. Stratocumulus castellanus should not be confused with stratocumulus
pierced by cumulus
. See cloud classification
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