(a) TECHNICAL SPECIFICATION
(i) These two species of Altocumulus have a cumuliform appearance; this feature is more marked in Altocumulus castellanus than in Altocumulus floccus.
(ii) Altocumulus castellanus is composed of turrets that appear to be arranged in lines; the turrets generally have a common horizontal base, which gives the cloud a crenellated (castle battlement) appearance.
(iii) Altocumulus floccus occur in white or grey scattered tufts with rounded and slightly bulging upper parts; they are often accompanied by fibrous trails (virga). These clouds resemble very small, more or less ragged Cumulus.