cirrocumulus n : a cloud at a high altitude consisting of a series of regularly arranged small clouds resembling ripples [syn: cirrocumulus cloud] [also: cirrocumuli (pl)]

English

Noun

1. In the context of "physics|Meteorology": A principal high-level cloud type appearing as a thin, white patch of cloud without shadows, composed of very small droplets in the form of grains or ripples. The elements may be merged or separate, and more or less regularly arranged; they subtend an angle of less than 1° when observed at an angle of more than 30° above the horizon. Holes or rifts often occur in a sheet of cirrocumulus. Abbreviated Cc.

Translations

• Italian: cirrocumulo
• Japanese: 巻積雲
• Russian: перисто-кучевая

References

• Source: FM 3-6 Field Behavior of NBC Agents.

Cirrocumulus clouds are high-altitude cloud, usually occurring at 16,000-40,000 feet. Like other cumulus clouds, cirrocumulus clouds signify convection. Unlike other cirrus clouds, cirrocumulus include liquid water droplets, although these are in a supercooled state. Ice crystals are also present, and typically, the ice crystals cause the supercooled water drops in the cloud to rapidly freeze, transforming the cirrocumulus into cirrostratus. This process can also produce precipitation in the form of a virga consisting of ice or snow. Thus cirrocumulus clouds are usually short-lived.

Properly, the term cirrocumulus refers to each cloud, but is typically also used to refer to an entire patch of cirrocumulus. When used thusly, each cirrocumulus element is referred to as a "cloudlet".

By appearance, the cirrocumulus is a small, white patch or tuft without a gray shadow. It occurs in patches or sheets along with other cirrocumulus. These often are organized in rows like other cumulus, but since they are so small, cirrocumulus patches take on a finer appearance, sometimes referred to colloquially as "herringbone" or "mackerel". As cirrocumulus consists of water droplets, it does not have the distinctive veil-like or fibrous look of other Family A clouds, and consists of separate "cloudlets" that resemble altocumulus.

The cirrocumulus is distinguished from the somewhat similar altocumulus in several ways, although the two cloud types can occasionally occur together with no clear demarcation between them. Cirrocumulus generally occur at higher altitudes than altocumulus, and thus the "cloudlets" appear smaller as they are more distant from observation at ground level. They are also colder. Cirrocumulus clouds never cast self-shadows and are translucent to certain degree. They are also typically found amongst other cirrus clouds in the sky, and are usually themselves seen to be transforming into these other types of cirrus.