| definition |
- A species of cumulonimbus cloud evolving from cumulus congestus.
The protuberances of its upper portion have begun to lose their cumuliform outline; they loom and usually flatten, then transform into a whitish mass with more or less diffuse outlines and vertical striations. Cirriform cloud is not present, but the transformation into ice crystals often proceeds with great rapidity. Most often, this cloud is accompanied by showers. By convention, the name cumulonimbus calvus is given to any highly developed cumuliform cloud that produces lightning, thunder, or hail, although the top shows no obvious trace of transformation into ice. The species calvus is unique to the genus cumulonimbus.
|
| Abstract from DBPedia | Cumulonimbus calvus is a moderately tall cumulonimbus cloud that is capable of precipitation but has not yet reached the tropopause, which is the height of stratospheric stability at which cumulonimbus forms into cumulonimbus capillatus (fibrous-top) or cumulonimbus incus (anvil-top). Cumulonimbus calvus develops from cumulus congestus, and its further development, under auspicious conditions, will result in cumulonimbus incus. This cloud consists mainly of water droplets. By definition of cumulonimbus cloud, at its top water droplets are transformed into ice crystals. But for cumulonimbus calvus, content of ice crystals are meager and polar are in early stage, so cloud tops still look round and puffy. Cumulonimbus calvus is characterized by distinctive (between other types of cumulonimbus cloud) rounded shape and relatively sharp edges of its top area, unlike cumulonimbus incus or cumulonimbus capillatus, which have cirriform tops. Developing cumulonimbus calvus lose sharp outlines of the top as more water droplets transform into ice crystals. Strong updrafts may form pileus or thin vertical stripes may protrude upwards out of the cloud. When upper parts of the cloud freeze to a greater extent and clearly visible cirriforms appear, cumulonimbus calvus metamorphoses into another species of cumulonimbus. Cumulonimbus calvus arcus is a sub-form of cumulonimbus calvus, which has arcus cloud ahead of cloud's front.無毛雲（むもううん、Calvus）とは、積乱雲に見られる雲種の1つである。無毛積乱雲とも言う。積乱雲のうち、雲頂が丸く、毛羽立ったような雲が付いていない状態のものを指す。驟雨や雷を伴うことが多いが、外観上は雄大雲との区別が難しい。 "Calvus"はラテン語で「むき出しの、露出した」といった意味があり、これにちなんで名づけられた。 (Source: http://dbpedia.org/resource/Cumulonimbus_calvus) |
