Perlucidus is a cloud variety that generally appears in only two cloud types, those being

altocumulus Altocumulus () is a middle-altitude cloud genus that belongs mainly to the physical category, characterized by globular masses or rolls in layers or patchesthe individual elements being larger and darker than those of cirrocumulus and smaller t ...

and

stratocumulus A stratocumulus cloud, occasionally called a cumulostratus, belongs to a genus-type of clouds characterized by large dark, rounded masses, usually in groups, lines, or waves, the individual elements being larger than those in altocumulus, and the ...

. Perlucidus cloud is easily recognizable by the small ubiquitous gaps that let higher clouds be seen. It forms when shallow

convection Convection is single or Multiphase flow, multiphase fluid flow that occurs Spontaneous process, spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoy ...

starts in a cloud layer that did not previously have perlucidus variety characteristics. The gaps between the cloud indicate regions where air is sinking. This cloud variety may appear either as a

translucent In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable light scattering by particles, scattering of light. On a macroscopic scale ...

cloud or an opaque cloud.

References

Cloud types {{Cloud-stub

See also

References