Cloud iridescence

Cloud iridescence
Cloud iridescence

Cloud iridescence is the occurrence of colors in a cloud similar to those seen in oil films on puddles, and is similar to irisation. It is a fairly uncommon phenomenon, most often observed in altocumulus, cirrocumulus and lenticular clouds, and very rarely in Cirrus clouds.[1][2][3] The colors are usually pastel, but can be very vivid. Iridescence is generally produced near the sun, with the sun's glare masking it, so it is more easily seen by hiding the sun behind a tree or building. Other aids are dark glasses, or observing the sky reflected in a convex mirror or in a pool of water.

Iridescent clouds are a diffraction phenomenon cause by small water droplets or small ice crystals individually scattering light. Larger ice crystals produce halos, which are a refraction phenomena rather than iridescence. Iridescence should similarly be distinguished from the refraction in larger raindrops that makes a rainbow.

If parts of clouds have small droplets or crystals of similar size, their cumulative effect is seen as colors. The cloud must be optically thin, so that most rays encounter only a single droplet. Iridescence is therefore mostly seen at cloud edges or in semi-transparent clouds, and newly forming clouds produce the brightest and most colorful iridescence. When a thin cloud has droplets of similar size over a large extent, the iridescence takes on the structured form of a corona, a central bright disk around the sun or moon surrounded by one or more colored rings.

See also

References

External links



Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Iridescence — Pearlescent redirects here. For the type of paint, see Pearlescent coatings. Iridescent redirects here. For the Linkin Park song, see Iridescent (song). Iridescence in soap bubbles …   Wikipedia

  • Cloud — For other uses, see Cloud (disambiguation). Cumulus cloudscape over Swifts Creek, Australia A cloud …   Wikipedia

  • Polar stratospheric cloud — Antarctic stratospheric cloud (nacreous clouds) Abbreviation PSC Altitude 15,000–25,000 m (50,000–80,000 ft) …   Wikipedia

  • Noctilucent cloud — Polar mesospheric cloud Noctilucent clouds over Kuresoo bog, Viljandimaa, Estonia Abbreviation NLC/PMC Altitude …   Wikipedia

  • nacreous cloud — A highly layered cloud with an iri descent appearance. It is akin to high altitude cirrus clouds. Also called a mother of pearl cloud. Clouds of unknown composition, whose form resembles that of cirrus or altocumulus lenticularis. These clouds… …   Aviation dictionary

  • Circumhorizontal arc — in relation to 22° arc, Oregon A circumhorizontal arc is an optical phenomenon an ice halo formed by plate shaped ice crystals in high level cirrus clouds. The current accepted names are circumhorizon arc or lower symmetric 46° plate arc[1] The… …   Wikipedia

  • Diffraction grating — A very large reflecting diffraction grating. In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The directions of these beams …   Wikipedia

  • Optical phenomenon — An optical phenomenon is any observable event that results from the interaction of light and matter. See also list of optical topics and optics. A mirage is an example of an optical phenomenon. Common optical phenomena are often due to the… …   Wikipedia

  • Diffraction — Computer generated intensity pattern formed on a screen by diffraction from a square aperture …   Wikipedia

  • atmosphere — atmosphereless, adj. /at meuhs fear /, n., v., atmosphered, atmosphering. n. 1. the gaseous envelope surrounding the earth; the air. 2. this medium at a given place. 3. Astron. the gaseous envelope surrounding a heavenly body. 4. Chem. any… …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”