Altocumulus cloud 高积云
（重定向自Altocumulus）
Altocumulus (From Latin Altus, "high", cumulus, "heaped") is a middle-altitude cloud genus that belongs to the stratocumuliform physical category characterized by globular masses or rolls in layers or patches, the individual elements being larger and darker than those of cirrocumulus and smaller than those of stratocumulus. Like other cumuliform and stratocumuliform clouds, altocumulus signifies convection. It is usually white or grey, and often occurs in sheets or patches with wavy, rounded masses or rolls. A sheet of partially conjoined altocumulus perlucidus is sometimes found preceding a weakening warm front, where the altostratus is starting to fragment, resulting in patches of altocumulus perlucidus between the areas of altostratus. Altocumulus is also commonly found between the warm and cold fronts in a depression, although this is often hidden by lower clouds.
