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Optical effects of atmosphere

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Deepa Mannarakoth
Deepa Mannarakoth

light and atmosphere

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Atmospheric Optics
Atmospheric optics and radiation: Visibility - attenuation of light, turbidity Optical phenomena rainbows haloes corona glory mirage blue of the sky colours at sunrise and sunset atmospheric refraction, Radiation in the atmosphere The spectrum, black body radiation, scattering
Optical effects of atmosphere
http://en.wikipedia.org/wiki/Rainbows
Optical effects of atmosphere
Optical effects of atmosphere
Rainbows come from the interaction of sunlight with round water droplets preferred single-reflection path with ~42属 deflection angle see http://mysite.verizon.net/vzeoacw1/rainbow.html drag incoming ray, and you get a stationary behavior at 42 rainbow arc always centered on anti-solar point different colors refract at slightly different angles owes to differences in refractive index for different colors Spring 2008 7 red appears higher in sky than bluesingle bounce; red & blue paths different
Rainbows come in pairs Spring 2008 8 Secondary rainbow has two reflections. Red now appears lower than blue in the sky. Beautiful double rainbow in Zion National Park. The primary is brighter, and the color sequence is reversed from that seen in fainter secondary. Area between rainbows often seen to be darker than elsewhere. .
Questions Which general direction will a rainbow be found in the evening? Why dont you see rainbows during the middle of the day? Spring 2008 9
The primary rainbow is a circle with radius 42属 and its center at your heads shadow.
犂犂巌患犂逗寛犁犂迦 - Rainbow
犂蹝園犂園患 犁犂 犂伍款犂о款犂萎苅犂 犁犂 犂犂犂犂鉦換犂萎患 犁犂 犂犂鉦寛犁犂犂犂逗犂む姦犁犂犁犂犁 犂伍款犂о姦犂む犂橿 犂犂橿犂橿瓦 犂犂鉦姦 犂犂犂鉦感犂犂鉦幹犁犂犂犂鉦苅犁 犂犂巌患犂逗寛犁犂迦. 犂犂む 犂犂鉦苅犂鉦瓦犁犂む患犂萎 犂犂犁犂犂鉦患犂逗寛犁犂, 犂犂犁犂犂鉦寛犁 犂犂む 犂犂犁犂 犂犂犂む犂む款犂犁 犂犂犂鉦犂 犂犂逗寛犁犂犂鉦瓦犁犂む患犂 犁犂. 犂犂犂鉦感犂む犂む 犂犁犂犂犁犂む歓 犂朽完犁犂犂鉦喚犂犂鉦姦犂 犂犁犂む犂 犂犁犂 犂犂迦犂鉦患犂逗完 犂犁犂犂鉦苅犁 犂犂む. 犂犂巌姦犂逗寛犁 犂犂逗寒犂犁犂犂 犂犂犁犂犂逗寛犁 犂犂逗寒犂犁犂犂 犂 犂劇款犂萎犁犂犂橿歓犂迦 (dews) 犂犂逗寒犂犁犂犂 犂朽寒犁犂 犂犂迦犂犂犂犁犂犂橿款犂犁 犂犂巌患犂逗寛犁犂迦 犂犂犁犂犂鉦 犂犁犂犂む. 犂犂巌犂犂犁犂犁犂犁犂 犂伍款犂項犂萎姦犂犁犂犂橿犂犁 犂 犂園犂 犂犂朽干犁犂橿犁犂犂鉦犁犂犂犁犂犂橿犂犁 犂伍堪犁犂犂犁犂犂犁犂謹犁犂犂橿歓犂迦 犁犂 犂犂巌患犂逗寛犁犂迦 犂朽干犂犂 犂伍款犂о款犂萎苅犂犂鉦苅犁. 犂犂迦犂犂犂犁犂犂橿歓犂迦 犂犁犂犂犂朽感犂逗 犂犁犂 犂伍犂萎姦犂萎感犁犂犂 犂犁犂萎犂- 犂犂犁犂む完犂犁犂犂む歓犂犂迦犂犂む犂む歓犂犁 (Total Internal Reflection) 犂朽歓犂犂о姦犂犂鉦 犂犂 犁犂 犂犁犂犂朽完犁犂犂犁犂犂橿款犂犂 犂犂朽完犁犂犂逗完犂逗姦 犂犂 犁犂 犂犂犂犁犂犁犂犁犂 . 犂犂犂鉦瓦 犂犂 犂犂 犂犂迦犂犂犂む犂む歓犂迦 犂犂逗寒犁犂 犁犂 犂 犂園瓦犁犂 犂朽完 犂犁犂 犂萎感犁犂犂逗姦犁犂犁犂犁 犂蹝む款犂犁犂犁 40-42 犂÷歓犂犁犂萎 犂朽犂 犁犂逗感犂鉦患犂犂む歓犂犂鉦寒犁犂 犂犂犁犂犂鉦患犂鉦官 犂犁犂犁.
犂犂朽姦犂逗寛犁 犂む犂犁犂 犂犂迦犂犂逗官犂犁犂犂橿犂 犁犂 犂犂迦 犂犂む款犂む歓犂迦犂鉦苅犁 犂朽姦犂む歓犂犂鉦寒犁犂 犂伍犂犂犂朽歓犂 犂犁犂犂む. 犂蹝園犂園患 犁犂 犂 犂園犁犂犁 犂朽姦犂む歓犂犂鉦寒犁犂 犂伍犂犂犂朽歓犂 犂犁犂 犂 犂朽勘犁犂犁 犂犂逗官犁犂 犂 犂園瓦犁犂む款犂犂逗犁犂犁犁犂 犂蹝園犂園患 犁犂 犂犁犁 犂む寛犁 犂朽姦犂む歓犂犂鉦寒犁犂 犂伍犂犂犂朽歓犂 犂犁犂 犂朽姦犂迦犂園犂園 犂犂犂む犂む款犂犂逗犁犂犁犁犂 犂犂橿犂 犂犂 犂犂鉦勘犁犂 犂犂犂逗犁犂犂鉦苅犁 犂犂巌患犂逗寛犁犂迦 犂萎犂犁犂 犂犂犂鉦干犁犂橿犂犁犂犂む. 犂犂犂園犂園款犂 犂犁犂犂犂む姦犂犂 犂犂巌患犂逗寛犁犂迦 犂犂 犂犁犂犂犂む姦犂犂伍犂ム款犂犂む犂む 犂萎犂犁犂 犂犂犂鉦干犁犂橿犂犁犂 犂犂犁犂犂迦犂 犂犂犁犂犂む款犂犁. 犂犂逗犁犂犂橿 犂犂巌患犂逗寛犁犂迦歓犂犂 犂犁 犂む犂 犂犂鉦苅犂鉦寒犁 犂犂園犁犂犂逗姦犂鉦寛犁 犂犂萎歓犂犁犂犁犂犂迦 犁犂 犂犂む歓犂犂 犂犁 犂む犂む 犂犂逗犁犂犂逗寛犁犂. 犂犂犂む寒犂犁犂犂鉦幹 犁犂 犂犂逗犁犂犂橿 犂犂逗寛犁犂 犂犁犂 犂伍犂ム款犂犂む犂 犂犂逗寒犁犂 犁犂 犂犂 犂犁犂犂犂む姦犂犁犂逗感犂犂逗寛犁 犂犂 犂犁犂犂犂む姦犂 犂犂犂鉦苅犂橿患犂逗寛犁 犂犂犁 犂犂鉦苅犂犂犁犂犁 犂犁犂犂む.
A halo is a ring of light surrounding the sun or moon. Most halos appear as bright white rings but in some instances, the dispersion of light as it passes through ice crystals found in upper level cirrus clouds can cause a halo to have color.
Halo Halos are caused by the light of the sun or moon passing through a very thin layer of cirriform[Cirrocumulus and cirrostratus ] (ice-crystal) clouds in the upper atmosphere. The ice crystals refract the light of the moon, similar to the way water droplets in the lower atmosphere can refract sunlight to produce a rainbow. Just like a rainbow, strong halos can have bands of color in them, due to slightly different refractive properties of the ice crystals for different colors. Essentially, halos ARE rainbows caused by primary refraction in ice crystals. http://curious.astro.cornell.edu/question.php?number=79
Anatomy of a Moon Halo The ring that appears around the moon arises from light passing through six-sided ice crystals high in the atmosphere. These ice crystals refract, or bend, light in the same manner that a camera lens bends light. The ring has a diameter of 22属 , and sometimes, if you are lucky, it is also possible to detect a second ring, 44属 diameter. Thin high cirrus clouds lofting at 20,000 feet or more contain tiny ice crystals that originate from the freezing of super cooled water droplets. These crystals behave like jewels refracting and reflecting in different directions. Cloud crystals are varieties of hexagonal prisms, (6 sides) and range in shapes from long columns to thin plate-like shapes that have different face sizes.
Light undergoes two refractions as it passes through an ice crystal and the amount of bending that occurs depends upon the ice crystal's diameter. http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/opt/ice/halo/22.rxml
A 22 degree halo develops when light enters one side of a columnar ice crystal and exits through another side. The light is refracted when it enters the ice crystal and once again when it leaves the ice crystal. The two refractions bend the light by 22 degrees from its original direction, producing a ring of light observed at 22 degrees from the sun or moon.
Optical effects of atmosphere
犂犂犁犂む完犁犂犁犂劇瓦犁犂む歓犂犂迦 犂伍歓犂園憾犁 犂犂犂犂犁犂犂橿歓犂迦 犂萎犂犂犂犁犂犁 犂犁犂 犂犂伍 犂犂萎寛犁 犂犂橿犂 犂橿歓犂迦 犂犂朽犁犂犁 犂犁犂犂犂鉦感犂む犂む歓犂犁 犂伍犂犂犂朽歓犂 犂犁犂 犂犂犂朽完犁犂む犂む寒犂犂鉦苅犁 犂 犂犁犂犂む歓犂犂鉦憾犂む犂む歓犂犁 犂犂逗寒犁犂犂逗寛犁. 犂犂む 犂伍犂萎姦犂犁犂犂犂鉦感犂む犂む歓犂 犁犂 犂犂犁犂萎寒犂逗寛犁犂鉦患犂逗寒 犁犂 犂犂 犂犂犂鉦犂迦 犂犂鉦冠犂犂犂鉦犂犂犁犂犂逗寛犁 犁犂, 犂萎款犂犁犂む歓 犂犂逗寛犁犂鉦患犂逗寛犁 犂犂む 犂犂鉦苅犂鉦寒犁 犂犂犁 犂犁犁 犂む寛犁 犂朽姦犂犁犂む瓦犂 犁犂 犂犁犂犂萎歓犂 犁犂. 犂犂逗寛犁 犂萎款犂犁犂む歓犂犂橿歓犂迦 犂犁犂萎犂犂犂犁犂萎寒犁 (犂犂犂迦犂迦犁犂犂逗寛犁 犂犂犁犂萎犂犂犂逗寒犂犂鉦犁 犂犁 犂む犂 犂蹝犂む犁犂犂逗寛犁 犁犂 犁犂逗患犂伍犂) 犂む歓犂橿犁犂 犂犁犂 犂犂朽憾犂萎犁犂犂橿歓犂迦 犂犂犁犂萎寒 犂 犂園犂園犁犂 犂犂犁犂萎犂犂犂鉦干犁 犂蹝む款犂犁犂犁 20 犂犁犂犁犂犁 犂朽姦犂鉦憾犂 犂橿犂 犂犂 犂朽寛犁犂犁犂 犂犂犁犂犂逗犁犂犂逗寒犂迦犂? 犂犂犁犂萎患犂迦犂犁犂, 犂犂犂迦犂迦犁犂犂逗寛犁 犂迦犁犂犂鉦完犁 犂犂項寒犂犂迦款 犂犂犁犂犂園歓犂犂犂犁犂犁 犂犁犂 犂犂む 犂犂 22o 犂犂項寒犂犂迦款 犂犁犂犂む歓犂犂鉦憾犂犂鉦苅犁.
犂犂む 犂犂犂鉦感犂む犂む 犂犂鉦苅 犂犁犂犂む歓犂犁 犂犂逗寛犁 犂伍款犂項犂萎姦犂犁犂犂橿 犂犂朽感犂犂犂鉦苅犁. 犂犁犂犂犂鉦感犂犂む犂 '犂朽干犂犂犁犂犂鉦犂逗 犂犁犂犂む歓犂犁' 犂劇粥犁犂 犂犂鉦犁犂む歓犂犂逗寛犁 犂犂橿犂 犂犂伍 犂犂萎寛犁 犂犂橿 犂犂橿犂 犂伍歓犂園憾犁 犂犂犂犂犁犂犂橿犂犁 犂伍款犂犁犂犂逗冠犂犁犂, 犂犂逗犂犁犂 犂犁犂謹侃犁犂о姦犂逗寛犁犂犂犁犂犁犂鉦寒犁 犂犂鉦勘犁犂む犂 犂犁犂犂犂鉦感犁犂 犂 犂園犂犁犂犁 犂朽歓犂 犂犁犂犂朽歓犂о犂 犂犂犁犂萎犂犂犂逗寒犂犂鉦犁 犂犁 犂む犂 犂犂犁犂萎寒犁犂犂 犂犂 phase. 犂劇粥犁犂 犂犂鉦犁犂む歓犂犂逗寛犁 犂犂橿犂 犂犂 犂犂伍 犂犂萎寛犁犂逗寒犁犂犂 犂犂橿犂橿歓犂犂迦犂犁 犂犁犂犂犂朽感犂逗 犂犁犂 犂犂 犂犁犂犂犂鉦感犂犂逗完犂犁犂 犂 犂園瓦犁犂 犂朽完 犂犂犂鉦干犁 犂犂む歓犂犁犂犂 犁犂逗感犂犂逗寛犁 22o 犂 犂む寛犁 50o 犂朽犂 犂朽姦犂む歓犂犂鉦寒犁犂 犂朽完犂鉦犂. 犂犂む歓犂迦 犂蹝園犂園患 犁犂 犂朽姦犂む歓犂犂鉦寒犁犂 犂 犂園犁犂 犂萎感犁犂犂逗犂橿 (犂犂む款犂犂む 22o犂萎感犁犂犂逗犂橿) 犂蹝園犂園患 犁犂 犂犁犁 犂む寛犁 犂犁犂犂犂鉦感犂犂鉦寒犂犂鉦姦 犂犂 犂犂朽犂 犂犂犁犂犂鉦 犁犂. 犂犂 犂犂犂鉦犂迦 犂犂犂鉦犂逗犂犂犂逗寒 犂犂伍 犂犂萎寛犁 犂犂橿款犂犁 犂犂 犂伍歓犂園憾犁 犂犂犂犂犂鉦干犂逗姦犂逗寛犁 犂犂犁犂犂鉦患 犂. 犂犁犂犂逗姦犂逗寛犁 犂犂逗寒犁犂 犂犂萎款犂橿 犂犂犂鉦 犂犂犂鉦干犁 犂犂朽姦犂逗寛犁 犂 犂犂 犂犂鉦完犁犂 犂犁犂犂犂鉦感犂む犂む歓犂犁 犂迦犁犂犂犂犂鉦姦犂逗犁犂犂鉦姦犂逗完犂逗 犁犂 犂む歓犂萎歓犂犁犂犂逗完犂逗 犂犁犂犂む (align 犂犂犂犁犂犁犂む歓犂萎歓犂 犂犁犂犂む). 犂犂朽姦犂逗寛犁 犂犂逗寒犁犂 犁犂 犂朽完 犂犁犂 犂萎感犁犂犂逗犂橿 22o 犂犂項寒犂犂迦款 犂伍犂劇犂犂逗 犂犁犂 . 犂犁犂犂逗姦犂逗寛犁 犂犂犂園犂園款犂 犂犂鉦完犂む犂む 犂犂逗寒犁犂犁 犂犂犂鉦 犂犁犂 犂犂橿犂 犁犂 犂犂項寒犂犂迦款 犁犁犂謹姦犂犂鉦苅犁, 犂犂む 犂犂朽犂 犂犂 犂犁犂犁犂犁犂 犂犂伍 犂犂萎寛犁 犂犂橿款犂犂逗完犂逗 犁犂 犂伍犂劇犂犂逗 犂犁犂犂む 犂犂犁犂 犂犂鉦勘犁犂む犂. 犂犂巌患犂逗寛犁犂迦犁犂 犂犂 犁犂 犂む堪犁犂犂逗寛犁 犂橿犂 犂犁犂犂о款犂犂朽姦犂む姦犂鉦憾犁犂 犂朽姦犂犁犂む堪犂鉦苅犂犂迦犂迦款- 犂犂巌患犂逗寛犁犂迦 犂犂迦犂犂鉦慣犁犂犂む犂む歓犂犁犂犂園姦 犁犂 犂犂項寒犂犂迦款 犂犂伍歓犂犁犂犂園姦 犁犂 犂伍犂劇犂犂逗姦犂鉦苅犁.
Corona Moon Corona Another interesting effect caused by moon light is the corona. Just like lunar halos, coronas are produced by high thin clouds. But unlike halos coronas are very small in size.
Coronas produced by diffraction of light When the distance between the drops is similar to the wavelength of visible light, the light that shines through the cloud droplets is diffracted and dispersed in the manner shown below. On a clear night, for example, the light you see coming from the moon is coning straight from the moon. However if a thin cloud layer is found between the observer and the moon, the diffraction and dispersion of the moonlight actually casts a light larger than the original light source. This 'crown' of light around the sun or moon is called the corona.
When the cloud droplets are very uniform in size, the diffracted light can cause the corona to be separated into its component colors, with blue light to the inside of the red light. These colors may repeat themselves, surrounding the moon with a series of colored rings, becoming fainter as each subsequent ring is located further from the moon. Also, a combination of refraction, reflection and diffraction can combine to produce other optical effects such as glories and the "Heiligenschein" effect -- which is a bright area around the head of an observer's shadow on a surface containing spherical water droplets. Glories are the rings of illuminated light seen most commonly from plane's shadows as they fly over clouds of liquid water. In both phenomena, the light ultimately is bent close to 180属 right back to the observer.
As a beam of light encounters a water droplet, it is refracted as it enters the droplet. Portions of the light are then internally reflected off the backside of the droplet. Before the light exits the droplet completely, it diffracts along the droplet's outer surface for just an instant as a surface wave before refracting as it leaves the droplet.
Glory
The backscattering (see section 7) of sunlight by water droplets in cloud causes the phenomenon of glory. Also, the colour of the rings is usually slightly faint. The size of the luminous rings is quite small. The colours of the rings are different and could repeat roughly in order for more rings extending outward. "Glory" is a set of small luminous rings of different colours appearing around the antisolar point (Fig.3) of the observer such that the sun, the observer and the observer's shadow inside the "glory" are simultaneously lying on a straight line. Since the luminous rings surrounding the aeroplane have different colours in order and their size are small, the phenomenon is "glory".
Optical effects of atmosphere
Is "Glory" a rare phenomenon? In the era of no airplane, sightings of glories were relatively rare. However, one who climbs up a mountain may also have the opportunity to see similar phenomenon. A mountaineer could sometimes observe glory with his shadow projected on fog or clouds when the sun shined from behind the mountaineer. When the sun is at relatively low altitude near the sunset or sunrise time, the shadow of the observer's lower half body could be enormously elongated and is thus apparently magnified. The observer's shadow, cast on fog or clouds and surrounded by a series of concentric coloured glowing rings of a glory, is called the Brocken Spectre (Fig.5). If there is more than one mountaineer, each one could see the shadows of other mountaineers. However, each mountaineer sees one glory only around the shadow of his own head as center of the glory and sees no other glory around the heads (as center of glory) of other mountaineers' shadows.
Optical effects of atmosphere
How are glories formed? What characteristics do glories have? Glories are caused by backscattering (see section 7) of sunlight from droplets of water in clouds or fog and appear against the nearly white background of clouds or fog. Glories are brighter with multiple rings and high color purity when the size of the water droplets is very uniform. The slightly faint colours of the rings in a glory change in the order from red to orange, yellow, green, blue, and violet inward towards the center or the antisolar point. Surface tension ensures that small water droplets are spherical. The visual angular size of a specific ring is approximately inversely proportional to the size of water droplets. Philip Laven found that most glories are caused by spherical water droplets with radii between 4 and 25 袖m. For droplets with radius being 10 袖m, the innermost red ring appears at a radius of angular width of about 2.4 degrees from the antisolar point. Stanley D. Gedzelman opined that glories are generally more distinct for cloud with droplets of about 10 袖m in radius. When droplet radius increases, the glory shrinks and becomes less prominent. http://www.weather.gov.hk/education/edu06nature/ele_glory1106_e.htm#q3
Mirage
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirari, meaning "to look at, to wonder at". This is the same root as for "mirror" and "to admire". In contrast to a hallucination, a mirage is a real optical phenomenon which can be captured on camera, since light rays actually are 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. 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.
Optical effects of atmosphere
Optical effects of atmosphere

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Optical effects of atmosphere

  • 2. Atmospheric optics and radiation: Visibility - attenuation of light, turbidity Optical phenomena rainbows haloes corona glory mirage blue of the sky colours at sunrise and sunset atmospheric refraction, Radiation in the atmosphere The spectrum, black body radiation, scattering
  • 7. Rainbows come from the interaction of sunlight with round water droplets preferred single-reflection path with ~42属 deflection angle see http://mysite.verizon.net/vzeoacw1/rainbow.html drag incoming ray, and you get a stationary behavior at 42 rainbow arc always centered on anti-solar point different colors refract at slightly different angles owes to differences in refractive index for different colors Spring 2008 7 red appears higher in sky than bluesingle bounce; red & blue paths different
  • 8. Rainbows come in pairs Spring 2008 8 Secondary rainbow has two reflections. Red now appears lower than blue in the sky. Beautiful double rainbow in Zion National Park. The primary is brighter, and the color sequence is reversed from that seen in fainter secondary. Area between rainbows often seen to be darker than elsewhere. .
  • 9. Questions Which general direction will a rainbow be found in the evening? Why dont you see rainbows during the middle of the day? Spring 2008 9
  • 10. The primary rainbow is a circle with radius 42属 and its center at your heads shadow.
  • 12. 犂蹝園犂園患 犁犂 犂伍款犂о款犂萎苅犂 犁犂 犂犂犂犂鉦換犂萎患 犁犂 犂犂鉦寛犁犂犂犂逗犂む姦犁犂犁犂犁 犂伍款犂о姦犂む犂橿 犂犂橿犂橿瓦 犂犂鉦姦 犂犂犂鉦感犂犂鉦幹犁犂犂犂鉦苅犁 犂犂巌患犂逗寛犁犂迦. 犂犂む 犂犂鉦苅犂鉦瓦犁犂む患犂萎 犂犂犁犂犂鉦患犂逗寛犁犂, 犂犂犁犂犂鉦寛犁 犂犂む 犂犂犁犂 犂犂犂む犂む款犂犁 犂犂犂鉦犂 犂犂逗寛犁犂犂鉦瓦犁犂む患犂 犁犂. 犂犂犂鉦感犂む犂む 犂犁犂犂犁犂む歓 犂朽完犁犂犂鉦喚犂犂鉦姦犂 犂犁犂む犂 犂犁犂 犂犂迦犂鉦患犂逗完 犂犁犂犂鉦苅犁 犂犂む. 犂犂巌姦犂逗寛犁 犂犂逗寒犂犁犂犂 犂犂犁犂犂逗寛犁 犂犂逗寒犂犁犂犂 犂 犂劇款犂萎犁犂犂橿歓犂迦 (dews) 犂犂逗寒犂犁犂犂 犂朽寒犁犂 犂犂迦犂犂犂犁犂犂橿款犂犁 犂犂巌患犂逗寛犁犂迦 犂犂犁犂犂鉦 犂犁犂犂む. 犂犂巌犂犂犁犂犁犂犁犂 犂伍款犂項犂萎姦犂犁犂犂橿犂犁 犂 犂園犂 犂犂朽干犁犂橿犁犂犂鉦犁犂犂犁犂犂橿犂犁 犂伍堪犁犂犂犁犂犂犁犂謹犁犂犂橿歓犂迦 犁犂 犂犂巌患犂逗寛犁犂迦 犂朽干犂犂 犂伍款犂о款犂萎苅犂犂鉦苅犁. 犂犂迦犂犂犂犁犂犂橿歓犂迦 犂犁犂犂犂朽感犂逗 犂犁犂 犂伍犂萎姦犂萎感犁犂犂 犂犁犂萎犂- 犂犂犁犂む完犂犁犂犂む歓犂犂迦犂犂む犂む歓犂犁 (Total Internal Reflection) 犂朽歓犂犂о姦犂犂鉦 犂犂 犁犂 犂犁犂犂朽完犁犂犂犁犂犂橿款犂犂 犂犂朽完犁犂犂逗完犂逗姦 犂犂 犁犂 犂犂犂犁犂犁犂犁犂 . 犂犂犂鉦瓦 犂犂 犂犂 犂犂迦犂犂犂む犂む歓犂迦 犂犂逗寒犁犂 犁犂 犂 犂園瓦犁犂 犂朽完 犂犁犂 犂萎感犁犂犂逗姦犁犂犁犂犁 犂蹝む款犂犁犂犁 40-42 犂÷歓犂犁犂萎 犂朽犂 犁犂逗感犂鉦患犂犂む歓犂犂鉦寒犁犂 犂犂犁犂犂鉦患犂鉦官 犂犁犂犁.
  • 13. 犂犂朽姦犂逗寛犁 犂む犂犁犂 犂犂迦犂犂逗官犂犁犂犂橿犂 犁犂 犂犂迦 犂犂む款犂む歓犂迦犂鉦苅犁 犂朽姦犂む歓犂犂鉦寒犁犂 犂伍犂犂犂朽歓犂 犂犁犂犂む. 犂蹝園犂園患 犁犂 犂 犂園犁犂犁 犂朽姦犂む歓犂犂鉦寒犁犂 犂伍犂犂犂朽歓犂 犂犁犂 犂 犂朽勘犁犂犁 犂犂逗官犁犂 犂 犂園瓦犁犂む款犂犂逗犁犂犁犁犂 犂蹝園犂園患 犁犂 犂犁犁 犂む寛犁 犂朽姦犂む歓犂犂鉦寒犁犂 犂伍犂犂犂朽歓犂 犂犁犂 犂朽姦犂迦犂園犂園 犂犂犂む犂む款犂犂逗犁犂犁犁犂 犂犂橿犂 犂犂 犂犂鉦勘犁犂 犂犂犂逗犁犂犂鉦苅犁 犂犂巌患犂逗寛犁犂迦 犂萎犂犁犂 犂犂犂鉦干犁犂橿犂犁犂犂む. 犂犂犂園犂園款犂 犂犁犂犂犂む姦犂犂 犂犂巌患犂逗寛犁犂迦 犂犂 犂犁犂犂犂む姦犂犂伍犂ム款犂犂む犂む 犂萎犂犁犂 犂犂犂鉦干犁犂橿犂犁犂 犂犂犁犂犂迦犂 犂犂犁犂犂む款犂犁. 犂犂逗犁犂犂橿 犂犂巌患犂逗寛犁犂迦歓犂犂 犂犁 犂む犂 犂犂鉦苅犂鉦寒犁 犂犂園犁犂犂逗姦犂鉦寛犁 犂犂萎歓犂犁犂犁犂犂迦 犁犂 犂犂む歓犂犂 犂犁 犂む犂む 犂犂逗犁犂犂逗寛犁犂. 犂犂犂む寒犂犁犂犂鉦幹 犁犂 犂犂逗犁犂犂橿 犂犂逗寛犁犂 犂犁犂 犂伍犂ム款犂犂む犂 犂犂逗寒犁犂 犁犂 犂犂 犂犁犂犂犂む姦犂犁犂逗感犂犂逗寛犁 犂犂 犂犁犂犂犂む姦犂 犂犂犂鉦苅犂橿患犂逗寛犁 犂犂犁 犂犂鉦苅犂犂犁犂犁 犂犁犂犂む.
  • 14. A halo is a ring of light surrounding the sun or moon. Most halos appear as bright white rings but in some instances, the dispersion of light as it passes through ice crystals found in upper level cirrus clouds can cause a halo to have color.
  • 15. Halo Halos are caused by the light of the sun or moon passing through a very thin layer of cirriform[Cirrocumulus and cirrostratus ] (ice-crystal) clouds in the upper atmosphere. The ice crystals refract the light of the moon, similar to the way water droplets in the lower atmosphere can refract sunlight to produce a rainbow. Just like a rainbow, strong halos can have bands of color in them, due to slightly different refractive properties of the ice crystals for different colors. Essentially, halos ARE rainbows caused by primary refraction in ice crystals. http://curious.astro.cornell.edu/question.php?number=79
  • 16. Anatomy of a Moon Halo The ring that appears around the moon arises from light passing through six-sided ice crystals high in the atmosphere. These ice crystals refract, or bend, light in the same manner that a camera lens bends light. The ring has a diameter of 22属 , and sometimes, if you are lucky, it is also possible to detect a second ring, 44属 diameter. Thin high cirrus clouds lofting at 20,000 feet or more contain tiny ice crystals that originate from the freezing of super cooled water droplets. These crystals behave like jewels refracting and reflecting in different directions. Cloud crystals are varieties of hexagonal prisms, (6 sides) and range in shapes from long columns to thin plate-like shapes that have different face sizes.
  • 17. Light undergoes two refractions as it passes through an ice crystal and the amount of bending that occurs depends upon the ice crystal's diameter. http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/opt/ice/halo/22.rxml
  • 18. A 22 degree halo develops when light enters one side of a columnar ice crystal and exits through another side. The light is refracted when it enters the ice crystal and once again when it leaves the ice crystal. The two refractions bend the light by 22 degrees from its original direction, producing a ring of light observed at 22 degrees from the sun or moon.
  • 20. 犂犂犁犂む完犁犂犁犂劇瓦犁犂む歓犂犂迦 犂伍歓犂園憾犁 犂犂犂犂犁犂犂橿歓犂迦 犂萎犂犂犂犁犂犁 犂犁犂 犂犂伍 犂犂萎寛犁 犂犂橿犂 犂橿歓犂迦 犂犂朽犁犂犁 犂犁犂犂犂鉦感犂む犂む歓犂犁 犂伍犂犂犂朽歓犂 犂犁犂 犂犂犂朽完犁犂む犂む寒犂犂鉦苅犁 犂 犂犁犂犂む歓犂犂鉦憾犂む犂む歓犂犁 犂犂逗寒犁犂犂逗寛犁. 犂犂む 犂伍犂萎姦犂犁犂犂犂鉦感犂む犂む歓犂 犁犂 犂犂犁犂萎寒犂逗寛犁犂鉦患犂逗寒 犁犂 犂犂 犂犂犂鉦犂迦 犂犂鉦冠犂犂犂鉦犂犂犁犂犂逗寛犁 犁犂, 犂萎款犂犁犂む歓 犂犂逗寛犁犂鉦患犂逗寛犁 犂犂む 犂犂鉦苅犂鉦寒犁 犂犂犁 犂犁犁 犂む寛犁 犂朽姦犂犁犂む瓦犂 犁犂 犂犁犂犂萎歓犂 犁犂. 犂犂逗寛犁 犂萎款犂犁犂む歓犂犂橿歓犂迦 犂犁犂萎犂犂犂犁犂萎寒犁 (犂犂犂迦犂迦犁犂犂逗寛犁 犂犂犁犂萎犂犂犂逗寒犂犂鉦犁 犂犁 犂む犂 犂蹝犂む犁犂犂逗寛犁 犁犂 犁犂逗患犂伍犂) 犂む歓犂橿犁犂 犂犁犂 犂犂朽憾犂萎犁犂犂橿歓犂迦 犂犂犁犂萎寒 犂 犂園犂園犁犂 犂犂犁犂萎犂犂犂鉦干犁 犂蹝む款犂犁犂犁 20 犂犁犂犁犂犁 犂朽姦犂鉦憾犂 犂橿犂 犂犂 犂朽寛犁犂犁犂 犂犂犁犂犂逗犁犂犂逗寒犂迦犂? 犂犂犁犂萎患犂迦犂犁犂, 犂犂犂迦犂迦犁犂犂逗寛犁 犂迦犁犂犂鉦完犁 犂犂項寒犂犂迦款 犂犂犁犂犂園歓犂犂犂犁犂犁 犂犁犂 犂犂む 犂犂 22o 犂犂項寒犂犂迦款 犂犁犂犂む歓犂犂鉦憾犂犂鉦苅犁.
  • 21. 犂犂む 犂犂犂鉦感犂む犂む 犂犂鉦苅 犂犁犂犂む歓犂犁 犂犂逗寛犁 犂伍款犂項犂萎姦犂犁犂犂橿 犂犂朽感犂犂犂鉦苅犁. 犂犁犂犂犂鉦感犂犂む犂 '犂朽干犂犂犁犂犂鉦犂逗 犂犁犂犂む歓犂犁' 犂劇粥犁犂 犂犂鉦犁犂む歓犂犂逗寛犁 犂犂橿犂 犂犂伍 犂犂萎寛犁 犂犂橿 犂犂橿犂 犂伍歓犂園憾犁 犂犂犂犂犁犂犂橿犂犁 犂伍款犂犁犂犂逗冠犂犁犂, 犂犂逗犂犁犂 犂犁犂謹侃犁犂о姦犂逗寛犁犂犂犁犂犁犂鉦寒犁 犂犂鉦勘犁犂む犂 犂犁犂犂犂鉦感犁犂 犂 犂園犂犁犂犁 犂朽歓犂 犂犁犂犂朽歓犂о犂 犂犂犁犂萎犂犂犂逗寒犂犂鉦犁 犂犁 犂む犂 犂犂犁犂萎寒犁犂犂 犂犂 phase. 犂劇粥犁犂 犂犂鉦犁犂む歓犂犂逗寛犁 犂犂橿犂 犂犂 犂犂伍 犂犂萎寛犁犂逗寒犁犂犂 犂犂橿犂橿歓犂犂迦犂犁 犂犁犂犂犂朽感犂逗 犂犁犂 犂犂 犂犁犂犂犂鉦感犂犂逗完犂犁犂 犂 犂園瓦犁犂 犂朽完 犂犂犂鉦干犁 犂犂む歓犂犁犂犂 犁犂逗感犂犂逗寛犁 22o 犂 犂む寛犁 50o 犂朽犂 犂朽姦犂む歓犂犂鉦寒犁犂 犂朽完犂鉦犂. 犂犂む歓犂迦 犂蹝園犂園患 犁犂 犂朽姦犂む歓犂犂鉦寒犁犂 犂 犂園犁犂 犂萎感犁犂犂逗犂橿 (犂犂む款犂犂む 22o犂萎感犁犂犂逗犂橿) 犂蹝園犂園患 犁犂 犂犁犁 犂む寛犁 犂犁犂犂犂鉦感犂犂鉦寒犂犂鉦姦 犂犂 犂犂朽犂 犂犂犁犂犂鉦 犁犂. 犂犂 犂犂犂鉦犂迦 犂犂犂鉦犂逗犂犂犂逗寒 犂犂伍 犂犂萎寛犁 犂犂橿款犂犁 犂犂 犂伍歓犂園憾犁 犂犂犂犂犂鉦干犂逗姦犂逗寛犁 犂犂犁犂犂鉦患 犂. 犂犁犂犂逗姦犂逗寛犁 犂犂逗寒犁犂 犂犂萎款犂橿 犂犂犂鉦 犂犂犂鉦干犁 犂犂朽姦犂逗寛犁 犂 犂犂 犂犂鉦完犁犂 犂犁犂犂犂鉦感犂む犂む歓犂犁 犂迦犁犂犂犂犂鉦姦犂逗犁犂犂鉦姦犂逗完犂逗 犁犂 犂む歓犂萎歓犂犁犂犂逗完犂逗 犂犁犂犂む (align 犂犂犂犁犂犁犂む歓犂萎歓犂 犂犁犂犂む). 犂犂朽姦犂逗寛犁 犂犂逗寒犁犂 犁犂 犂朽完 犂犁犂 犂萎感犁犂犂逗犂橿 22o 犂犂項寒犂犂迦款 犂伍犂劇犂犂逗 犂犁犂 . 犂犁犂犂逗姦犂逗寛犁 犂犂犂園犂園款犂 犂犂鉦完犂む犂む 犂犂逗寒犁犂犁 犂犂犂鉦 犂犁犂 犂犂橿犂 犁犂 犂犂項寒犂犂迦款 犁犁犂謹姦犂犂鉦苅犁, 犂犂む 犂犂朽犂 犂犂 犂犁犂犁犂犁犂 犂犂伍 犂犂萎寛犁 犂犂橿款犂犂逗完犂逗 犁犂 犂伍犂劇犂犂逗 犂犁犂犂む 犂犂犁犂 犂犂鉦勘犁犂む犂. 犂犂巌患犂逗寛犁犂迦犁犂 犂犂 犁犂 犂む堪犁犂犂逗寛犁 犂橿犂 犂犁犂犂о款犂犂朽姦犂む姦犂鉦憾犁犂 犂朽姦犂犁犂む堪犂鉦苅犂犂迦犂迦款- 犂犂巌患犂逗寛犁犂迦 犂犂迦犂犂鉦慣犁犂犂む犂む歓犂犁犂犂園姦 犁犂 犂犂項寒犂犂迦款 犂犂伍歓犂犁犂犂園姦 犁犂 犂伍犂劇犂犂逗姦犂鉦苅犁.
  • 22. Corona Moon Corona Another interesting effect caused by moon light is the corona. Just like lunar halos, coronas are produced by high thin clouds. But unlike halos coronas are very small in size.
  • 23. Coronas produced by diffraction of light When the distance between the drops is similar to the wavelength of visible light, the light that shines through the cloud droplets is diffracted and dispersed in the manner shown below. On a clear night, for example, the light you see coming from the moon is coning straight from the moon. However if a thin cloud layer is found between the observer and the moon, the diffraction and dispersion of the moonlight actually casts a light larger than the original light source. This 'crown' of light around the sun or moon is called the corona.
  • 24. When the cloud droplets are very uniform in size, the diffracted light can cause the corona to be separated into its component colors, with blue light to the inside of the red light. These colors may repeat themselves, surrounding the moon with a series of colored rings, becoming fainter as each subsequent ring is located further from the moon. Also, a combination of refraction, reflection and diffraction can combine to produce other optical effects such as glories and the "Heiligenschein" effect -- which is a bright area around the head of an observer's shadow on a surface containing spherical water droplets. Glories are the rings of illuminated light seen most commonly from plane's shadows as they fly over clouds of liquid water. In both phenomena, the light ultimately is bent close to 180属 right back to the observer.
  • 25. As a beam of light encounters a water droplet, it is refracted as it enters the droplet. Portions of the light are then internally reflected off the backside of the droplet. Before the light exits the droplet completely, it diffracts along the droplet's outer surface for just an instant as a surface wave before refracting as it leaves the droplet.
  • 26. Glory
  • 27. The backscattering (see section 7) of sunlight by water droplets in cloud causes the phenomenon of glory. Also, the colour of the rings is usually slightly faint. The size of the luminous rings is quite small. The colours of the rings are different and could repeat roughly in order for more rings extending outward. "Glory" is a set of small luminous rings of different colours appearing around the antisolar point (Fig.3) of the observer such that the sun, the observer and the observer's shadow inside the "glory" are simultaneously lying on a straight line. Since the luminous rings surrounding the aeroplane have different colours in order and their size are small, the phenomenon is "glory".
  • 29. Is "Glory" a rare phenomenon? In the era of no airplane, sightings of glories were relatively rare. However, one who climbs up a mountain may also have the opportunity to see similar phenomenon. A mountaineer could sometimes observe glory with his shadow projected on fog or clouds when the sun shined from behind the mountaineer. When the sun is at relatively low altitude near the sunset or sunrise time, the shadow of the observer's lower half body could be enormously elongated and is thus apparently magnified. The observer's shadow, cast on fog or clouds and surrounded by a series of concentric coloured glowing rings of a glory, is called the Brocken Spectre (Fig.5). If there is more than one mountaineer, each one could see the shadows of other mountaineers. However, each mountaineer sees one glory only around the shadow of his own head as center of the glory and sees no other glory around the heads (as center of glory) of other mountaineers' shadows.
  • 31. How are glories formed? What characteristics do glories have? Glories are caused by backscattering (see section 7) of sunlight from droplets of water in clouds or fog and appear against the nearly white background of clouds or fog. Glories are brighter with multiple rings and high color purity when the size of the water droplets is very uniform. The slightly faint colours of the rings in a glory change in the order from red to orange, yellow, green, blue, and violet inward towards the center or the antisolar point. Surface tension ensures that small water droplets are spherical. The visual angular size of a specific ring is approximately inversely proportional to the size of water droplets. Philip Laven found that most glories are caused by spherical water droplets with radii between 4 and 25 袖m. For droplets with radius being 10 袖m, the innermost red ring appears at a radius of angular width of about 2.4 degrees from the antisolar point. Stanley D. Gedzelman opined that glories are generally more distinct for cloud with droplets of about 10 袖m in radius. When droplet radius increases, the glory shrinks and becomes less prominent. http://www.weather.gov.hk/education/edu06nature/ele_glory1106_e.htm#q3
  • 33. A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirari, meaning "to look at, to wonder at". This is the same root as for "mirror" and "to admire". In contrast to a hallucination, a mirage is a real optical phenomenon which can be captured on camera, since light rays actually are 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. 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.

Editor's Notes

  1. 6/02/08
  2. 6/02/08
  3. 6/02/08