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Photometeor
In atmospheric optics, a photometeor is a bright object or other optical phenomenon appearing in the Earth's atmosphere when sunlight or moonlight creates a Specular reflection, reflection, refraction, diffraction or interference (optics), interference under particular circumstances. The most common examples include Halo (optical phenomenon), halos, rainbows, fogbows, cloud iridescences (or irisation), glory (optical phenomenon), glories, Bishop's Ring, Bishop's rings, corona (optical phenomenon), coronas, crepuscular rays, sun dog, sun dogs, light pillars, mirages, scintillation (astronomy), scintillations, and green flashes. Photometeors are not reported in routine weather observation. See also *Hydrometeor *Rayleigh scattering Notes and references External links South pole halos - an example of halos and arcs around the south polar sun
Atmospheric optical phenomena {{optics-stub sv:Meteor#Fotometeorer ...
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Cloud Iridescence
Cloud iridescence or irisation is a colorful optical phenomenon that occurs in a cloud and appears in the general proximity of the Sun or Moon. The colors resemble those seen in soap bubbles and oil on a water surface. It is a type of photometeor. This fairly common phenomenon is most often observed in altocumulus, cirrocumulus, lenticular, and cirrus clouds. They sometimes appear as bands parallel to the edge of the clouds. Iridescence is also seen in the much rarer polar stratospheric clouds, also called nacreous clouds. The colors are usually pastel, but can be very vivid or mingled together, sometimes similar to mother-of-pearl. When appearing near the Sun, the effect can be difficult to spot as it is drowned in the Sun's glare. This may be overcome by shielding the sunlight with one's hand or hiding it 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. Etymology Irisations are name ...
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Corona (optical Phenomenon)
In meteorology, a corona (plural ''coronae'') is an optical phenomenon produced by the diffraction of sunlight or moonlight (or, occasionally, bright starlight or planetlight) by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface. In its full form, a corona consists of several concentric, pastel-colored rings around the celestial object and a central bright area called an ''aureole''. The aureole is often (especially in case of the Moon) the only visible part of the corona and has the appearance of a bluish-white disk which fades to reddish-brown towards the edge. The angular diameter of a corona depends on the sizes of the water droplets involved; smaller droplets produce larger coronae. For the same reason, the corona is the most pronounced when the size of the droplets is most uniform. Coronae differ from halos in that the latter are formed by refraction (rather than diffraction) from comparatively large rather than sm ...
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Rayleigh Scattering
Rayleigh scattering ( ) is the scattering or deflection of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scattering medium (normal dispersion relation, dispersion regime), the amount of scattering is inversely proportional to the fourth power of the wavelength (e.g., a blue color is scattered much more than a red color as light propagates through air). The phenomenon is named after the 19th-century British physicist Lord Rayleigh (John William Strutt). Rayleigh scattering results from the electric polarizability of the particles. The oscillating electric field of a light wave acts on the charges within a particle, causing them to move at the same frequency. The particle, therefore, becomes a small radiating dipole whose radiation we see as scattered light. The particles may be individual atoms or molecules; it can occur when light travels throu ...
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Hydrometeor
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwealth usage), snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation; their water vapor does not condense sufficiently to precipitate, so fog and mist do not fall. (Such a non-precipitating combination is a colloid.) Two processes, possibly acting together, can lead to air becoming saturated with water vapor: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers ...
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Weather Observation
Weather reconnaissance is the acquisition of weather data used for research and planning. Typically the term reconnaissance refers to observing weather from the air, as opposed to the ground. Methods Aircraft Helicopters are not built to withstand the severe turbulence encountered in hurricane rainbands and eye walls. One reason is that a helicopter receives all of its lift from its rotating blades, and they are most likely to break off in hurricane conditions. The Lockheed C-130 Hercules is used as a weather reconnaissance aircraft, with 5 different versions being used. The current version is the Lockheed C-130J. The Lockheed WC-130J aircraft is a venerable aircraft for weather reconnaissance. It flies directly into the hurricane, typically penetrating the hurricane's eye several times per mission at altitudes between and . The 53rd WRS Hurricane Hunters operate ten WC-130J aircraft for weather reconnaissance. The WP-3D Orion aircraft flown by the NOAA Hurricane ...
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Green Flash
The green flash and green ray are meteorological optical phenomena that sometimes occur transiently around the moment of sunset or sunrise. When the conditions are right, a distinct green spot is briefly visible above the Sun's upper limb; the green appearance usually lasts for no more than two seconds. Rarely, the green flash can resemble a green ray shooting up from the sunset or sunrise point. Green flashes occur because the Earth's atmosphere can cause the light from the Sun to separate, via wavelength varying refraction, into different colors. Green flashes are a group of similar phenomena that stem from slightly different causes, and therefore, some types of green flashes are more common than others. Observing Green flashes may be observed from any altitude. They usually are seen at an unobstructed horizon, such as over the ocean, but are possible over cloud tops and mountain tops as well. They may occur at any latitude, although at the equator, the flash rarely l ...
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Scintillation (astronomy)
Twinkling, also called scintillation, is a generic term for variations in apparent brightness, colour, or position of a distant luminous object viewed through a medium.Wang, Ting-I; Williams, Donn"Scintillation technology bests NIST" , ''InTech'', May 1, 2005. If the object lies outside the Earth's atmosphere, as in the case of stars and planets, the phenomenon is termed ''astronomical scintillation''; for objects within the atmosphere, the phenomenon is termed ''terrestrial scintillation''. As one of the three principal factors governing astronomical seeing (the others being light pollution and cloud cover), atmospheric scintillation is defined as variations in illuminance only. In simple terms, twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Most scintillation effects are caused by anomalous atmospheric refraction caused by small-scale fluctuations in air density usually related to temperature gradients. Scinti ...
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Mirage
A mirage is a naturally-occurring optical phenomenon in which light rays bend via refraction to produce a displaced image of distant objects or the sky. The word comes to English via the French ''(se) mirer'', from the Latin ''mirari'', meaning "to look at, to wonder at". Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and " Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically stacked images, which form one rapidly-changing mirage. In contrast to a hallucination, a mirage is a real optical phenomenon that can be captured on camera, since light rays are actually refracted to form the false image at the observer's location. What the image appears to represent, however, is determined by the interpretive faculties of the human mind. For example, inferior images on land are very easily mistaken for the reflections from a small body of water. Inferior mirage In an inferior mirage, the mirage im ...
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Light Pillar
A light pillar or ice pillar is an atmospheric optics, atmospheric optical phenomenon in which a vertical light beam, beam of light appears to extend above and/or below a light source. The effect is created by the Reflection (physics), reflection of light from tiny ice crystals that are suspended in the atmosphere or that compose high-altitude clouds (e.g. cirrostratus or cirrus clouds). If the light comes sunlight, from the Sun (usually when it is near or even below the horizon), the phenomenon is called a sun pillar or solar pillar. Light pillars can also be caused moonlight, by the Moon or terrestrial sources, such as streetlights and erupting volcanoes. Formation Since they are caused by the interaction of light with ice crystals, light pillars belong to the family of halo (optical phenomenon), halos. The crystals responsible for light pillars usually consist of flat, Hexagonal crystal family, hexagonal plates, which tend to orient themselves more or less horizontally as th ...
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Sun Dog
A sun dog (or sundog) or mock sun, also called a parhelion (plural parhelia) in atmospheric science, is an atmospheric optical phenomenon that consists of a bright spot to one or both sides of the Sun. Two sun dogs often flank the Sun within a 22° halo. The sun dog is a member of the family of halos caused by the refraction of sunlight by ice crystals in the atmosphere. Sun dogs typically appear as a pair of subtly colored patches of light, around 22° to the left and right of the Sun, and at the same altitude above the horizon as the Sun. They can be seen anywhere in the world during any season, but are not always obvious or bright. Sun dogs are best seen and most conspicuous when the Sun is near the horizon. Formation and characteristics upA right-hand sun dog in Parry_arc.html" ;"title="Salem, Massachusetts. Also visible are a Parry arc">Salem, Massachusetts. Also visible are a Parry arc, an upper tangent arc, a 22° halo, and part of the parhelic circle. file:Dop ...
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Crepuscular Ray
Crepuscular rays, sometimes colloquially referred to as god rays, are sunbeams that originate when the Sun appears to be just above or below a layer of clouds, during the twilight period. Crepuscular rays are noticeable when the contrast (vision), contrast between light and dark is most obvious. Crepuscular comes from the Latin word , meaning "twilight". Crepuscular rays usually appear orange because optical path, the path through the atmosphere at dawn and dusk passes through up to 40 times as much air as rays from a high Sun at noon. particulates, Particles in the air light scattering by particles, scatter short-wavelength light (blue and green) through Rayleigh scattering much more strongly than longer-wavelength yellow and red light. Loosely, the term ''crepuscular rays'' is sometimes extended to the general phenomenon of rays of sunlight that appear to converge at a point in the sky, irrespective of time of day. A rare related phenomenon are anticrepuscular rays which can a ...
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