Fog bow

360 degrees fogbow
A fog bow, solar glory and Brocken spectre observed in San Francisco
A fog bow, solar glory and Brocken spectre observed in San Francisco
A fog bow and solar glory observed in San Francisco

A fog bow is a similar phenomenon to a rainbow, however, as its name suggests, it appears as a bow in fog rather than rain. Because of the very small size of water droplets that cause fog—smaller than 0.05 millimetres (0.0020 in)—the fog bow has only very weak colors, with a red outer edge and bluish inner.

In many cases when the droplets are very small, fog bows appear white, and are therefore sometimes called white rainbows. This lack of color is a distinguishing feature from a glory, which has multiple pale colored rings caused by diffraction. When the droplets forming it are almost all of the same size the fog bow can have multiple inner rings, or supernumeraries, that are more strongly colored than the main bow. According to NASA:

The fogbow's lack of colors is caused by the smaller water drops ... so small that the wavelength of light becomes important. Diffraction smears out colors that would be created by larger rainbow water drops ...[1]

A fog bow seen in clouds, typically from an aircraft looking downwards, is called a cloud bow. Mariners sometimes call fog bows sea-dogs.

Contents

Direction

A fog bow is seen in the same direction as a rainbow, thus the sun would be behind the head of the observer and the direction of view would be into a bank of fog (which may not be noticeable in directions away from the bow itself). Its outer radius is slightly less than that of a rainbow.

When a fog bow appears at night it is called a lunar fog bow.[2]

See also

References

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • fog|bow — «FOG BOH, FG », noun. a phenomenon like the rainbow, sometimes seen in fog …   Useful english dictionary

  • fog-bow — fogˈ bow noun A whitish arch like a rainbow, seen in fogs • • • Main Entry: ↑fog …   Useful english dictionary

  • bow — bow; bow·darc; bow·den; bow·dich·ia; bow·ditch; bow·dock; bow·el·less; bow·en·ite; bow·en s; bow·er barff; bow·er·ly; bow·et; bow·grace; bow·ing·ly; bow·kail; bow·legged; bow·less; bow·line; bow·man s; bow·ser; bow·sprit; bow·stave; bow·ster;… …   English syllables

  • fog — an·ti·fog·gant; an·ti·fog·mat·ic; be·fog; fog; fog·bow; fog·gage; fog·ga·ra; fog·gie; fog·gi·ly; fog·gi·ness; fog·less; pet·ti·fog; pet·ti·fog·ger; pet·ti·fog·gery; pet·ti·fog·ging; de·fog; fog·ger; fog·gy; de·fog·ger; …   English syllables

  • fog — 1. n. & v. n. 1 a a thick cloud of water droplets or smoke suspended in the atmosphere at or near the earth s surface restricting or obscuring visibility. b obscurity in the atmosphere caused by this. 2 Photog. cloudiness on a developed negative… …   Useful english dictionary

  • Fog eater — * In railroad slang an engineer * In motorcycling a trade name for helmet visors which don t fog. * In meteorology A white bow in the clouds during foggy weather is so called. Such a bow was seen in England during January, 1888. A week preceding …   Wikipedia

  • Fog — Cloud Cloud (kloud), n. [Prob. fr. AS. cl[=u]d a rock or hillock, the application arising from the frequent resemblance of clouds to rocks or hillocks in the sky or air.] 1. A collection of visible vapor, or watery particles, suspended in the… …   The Collaborative International Dictionary of English

  • fogbow — fog·bow …   English syllables

  • fogbow — fog•bow [[t]ˈfɒgˌboʊ, ˈfɔg [/t]] n. mer a bow or arc of white or yellowish hue seen in or against a fog bank; a rainbow formed by fog droplets • Etymology: 1825–35; fog+ (rain) bow …   From formal English to slang

  • Antonio de Ulloa — Born 12 January 1716(1716 01 12) Seville …   Wikipedia


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