Infralateral arc

Infralateral arc

An infralateral arc (or lower lateral tangent arc) is a rare halo, an optical phenomenon appearing similar to a rainbow under a white parhelic circle. Together with the supralateral arc they are always located outside the seldom observable 46° halo, but in contrast to supralateral arcs, infralateral arcs are always located below the parhelic circle.

The shape of an infralateral arc varies with the elevation of the sun. Between sunrise and before the sun reaches about 50° over the horizon, two infralateral arcs are located on either side (e.g. lateral) of the 46° halo, their convex apexes lying tangent to the 46° halo. As the sun reaches above 68° the two arcs unite to a single concave arc tangent to the 46° halo vertically under the sun.cite web
url = http://www.meteoros.de/arten/ee22e.htm
title = Infralateral arc | publisher = Arbeitskreis Meteore e.V.
accessdate = 07-04-16 | language = English
(Including a photo from January 1996 and a 1980 computer simulation of infra- and supralateral arcs relative to a 46° halo.)]

Infralateral arcs form when sun light enters horizontally oriented, rod-shaped hexagonal ice crystals through a hexagonal base and exits through one of the prism sides. Infralateral arcs occur about once a year. They are often observed together with circumscribed halos and upper tangent arcs.cite web
url = http://www.engl.paraselene.de/html/infralateral_arcs.html
title = Infralateral Arcs | publisher = www.paraselene.de
accessdate = 2007-04-16 | language = English
]

See also

* Circumzenithal arc
* Tangent arc
* Parry arc

References

External links

* [http://www.atoptics.co.uk/halo/supinf.htm Atmospheric Optics - Supralateral & infralateral arcs] - including HaloSim computer simulations and crystal illustrations.


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Arc — may refer to: Computing and gaming*Arc (programming language), a Lisp dialect in development by Paul Graham *.arc, a file extension for archive files *arc, the command line interface for ArcInfo *Arc System Works, a video game… …   Wikipedia

  • Supralateral arc — A supralateral arc is a rare halo, an optical phenomenon often confused with the indeed infrequently appearing 46° halo. Distinguishing between the two is furthermore difficult as supralateral arcs typically only appears in fragments while the… …   Wikipedia

  • 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

  • Parry arc — A Parry arc is a rare halo, an optical phenomenon which occasionally appears over a 22° halo together with a upper tangent arc. Discovery The halo was first described by Sir William Edward Parry (1790 1855) in 1820 during one of his Arctic… …   Wikipedia

  • Subhelic arc — A subhelic arc is a rare halo, formed by internal reflection through ice crystals, that curves upwards from the horizon and touches the tricker arc above the anthelic point. Subhelic arcs are a result of ray entrance and exit through prism end… …   Wikipedia

  • 46° halo — A 46° halo is a rare and huge halo, together with the smaller 22° halo a circular optical phenomenon centred on the sun. At sun elevations between 15 27°, it is often confused with the more colourful and frequently observed supralateral and… …   Wikipedia

  • Vädersolstavlan — Infobox Painting| title=Vädersolstavlan artist=Urban Målare, Jacob Elbfas year=1535, 1636 type=Oil on panel height=163 width=110 height inch=64 width inch=43 city=Stockholm museum=Storkyrkan audio|Vädersolstavlan.ogg|Vädersolstavlan (Swedish for… …   Wikipedia

  • Sun dog — For other uses, see Sun dog (disambiguation). Very bright sundogs in Fargo, North Dakota. Note the halo arcs passing through each sundog …   Wikipedia

  • Arco circunhorizontal — Saltar a navegación, búsqueda Arco circunhorizontal fotografiado en Coeur d Alene, Idaho el 3 de junio de 2006 …   Wikipedia Español

Share the article and excerpts

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