80 lines
4.7 KiB
Plaintext
80 lines
4.7 KiB
Plaintext
ÜÜÜÜÜÜÜÜÜÜÜÜÜ ÜÜÜ ÜÜÜÜ
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ÜÛÛÛÛÛÛÛÛßÛßßßßßÛÛÜ ÜÜßßßßÜÜÜÜ ÜÛÜ ÜÛÛÛÛÛÛÛÛÜÜÜÜÜÛßß ßÛÛ
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ßÛÛÛÛÛÛÛÛÛÛÛÛÛÛÜ ßÛÛ ÜÛÛÛÜÛÛÜÜÜ ßÛÛÛÛÜ ßÛÛÛÛÛÛÛÜÛÛÜÜÜÛÛÝ Ûß
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ßßßÛÛÛÛÛÛÛÛÛÛÜ ÞÝ ÛÛÛÛÛÛÛÛÛÛÛßßÛÜÞÛÛÛ ÛÛÛÛÛÜ ßßÛÛÛÞß
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Mo.iMP ÜÛÛÜ ßÛÛÛÛÛÛÛÝÛ ÞÛÛÛÛÛÛÛÛÛ ÞÛÛÛÛ ÞÛÛÛÛÛÝ ßÛß
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ÜÛÛÛÛÛÛÛ ÛÛÛÛÛÛÛÛÝ ÞÛÛÛÛÛÛÛÛÝ ÛÛÛ ÛÛÛÛÛÛ
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ÜÛÛÛÛÛÛÛÝ ÞÛÛÛÛÛÛÛÛ ÞÛÛÛÛÛÛÛÛ ß ÞÛÛÛÛÛÛÜ ÜÛ
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ÜÛÛÛÛÛÛÛÝ ÛÛÛÛÛÛÛÛ ÛÛÛÛÛÛÛÛÝ ÞÞÛÛÛÛÛÛÛÛÛß
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ÜÛßÛÛÛÛÛÛ ÜÜ ÛÛÛÛÛÛÛÛÝ ÛÛÞÛÛÛÛÛÝ ÞÛÛÛÛÛÛßß
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ÜÛßÛÛÛÛÛÛÜÛÛÛÛÜÞÛÛÛÛÛÛÛÛ ÞÛ ßÛÛÛÛÛ Ü ÛÝÛÛÛÛÛ Ü
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ÜÛ ÞÛÛÛÛÛÛÛÛÛÛß ÛÛÛÛÛÛÛÛÛ ßÛÜ ßÛÛÛÜÜ ÜÜÛÛÛß ÞÛ ÞÛÛÛÝ ÜÜÛÛ
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ÛÛ ÛÛÛÛÛÛÛÛß ÛÛÛÛÛÛÛÛÛÛÜ ßÛÜ ßßÛÛÛÛÛÛÛÛÛß ÜÜÜß ÛÛÛÛÜÜÜÜÜÜÜÛÛÛÛÛß
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ßÛÜ ÜÛÛÛß ßÛÛÛÛÛÛÛÛÛÛÜ ßßÜÜ ßßÜÛÛßß ßÛÛÜ ßßßÛßÛÛÛÛÛÛÛßß
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ßßßßß ßßÛÛß ßßßßß ßßßßßßßßßßßßß
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ARRoGANT CoURiERS WiTH ESSaYS
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Grade Level: Type of Work Subject/Topic is on:
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[ ]6-8 [ ]Class Notes [Essay on Forecasting ]
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[x]9-10 [ ]Cliff Notes [Storms ]
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[ ]11-12 [x]Essay/Report [ ]
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[ ]College [ ]Misc [ ]
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Dizzed: 12/94 # of Words:525 School: ? State: ?
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ÄÄÄÄÄÄÄÄÄ>ÄÄÄÄÄÄÄÄÄ>ÄÄÄÄÄÄÄÄÄ>Chop Here>ÄÄÄÄÄÄÄÄÄ>ÄÄÄÄÄÄÄÄÄ>ÄÄÄÄÄÄÄÄÄ>ÄÄÄÄÄÄÄÄÄ
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============================================================
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Haloes Forecast Storms NEWSCIENCE
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------------------------------------------------------------
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If you know where and when to look, you can treat yourself to a
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colourful display of atmospheric haloes, spots and pillars. These images
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can tell you something about the clouds overhead and possible changes in
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the weather.
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All of these images are created by light shining through cirrostratus
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clouds. These clouds occur at an altitude of 6,000-12,000 metres. They
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appear as a thin sheet or layer (strata) that is pure white. The layer of
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cloud is so thin (only 100-450 metres) that is doesn't obscure the sun or
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moon, so you should be able to see your shadow.
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Cirrostratus is made of many types of ice crystals. However, four
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crystal shapes are responsible for producing most of the commonly see
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haloes-plate crystals, columns, capped columns and bullets.
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The most obvious halo is found around the sun. If the layer of
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cirrostratus is extensive, you'll see an entire ring. Within the layer of
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cloud, sunlight is striking and passing through the sides of
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randomly-oriented ice crystals. As the sunlight passes through each
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crystal, the light changes direction, or refracts. The radius of the hale
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depends on the amount of change in the direction of the sun's light.
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Usually this is 22 degrees. Since the sun is 1/2 of a degree across, the
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radius of the halo is 44 sun-widths. Occasionally you may see a second
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halo at 46 degrees from the sun (that is, with a radius of 92 sun-widths).
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This is produced by sunlight passing through both the side and bottom of
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each crystal. Moonlight will also produce a halo, around the moon, with
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the proper layer of cirrostatus.
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Another common optical effect is known as "mock suns" or "sun dogs" or
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"parhelia" (Greek for "with the sun"). These bright spots on either side of
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the sun, outside of the halo, occur when sunlight passes through the sides
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of capped columns, bullets and plate crystals, when these crystals are
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arranged with their sides vertical. The crystals wobble, diffusing and
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smearing the colours of the mock sun.
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You can see haloes and mock suns more clearly if you block out your
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view of the real sun by holding your hand in front of it at arm's length.
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Another spectactular optical effect is the solar pillar. This is a
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vertical shaft of light the same colour as the sun stretching upwards from
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the sun and is most often seen at sunset or sunrise. It's produced by
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sunlight reflecting of the base of plate and capped column crystals in the
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clouds. You can also see pillars in an ice fog, when it's illuminated by
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streelights, or airport runway lights, for instance.
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The appearance of all these optical images is a good indication that
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the weather will change. Strong vertical air currents associated with low
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pressure storms carry moist air skyward, where the water freezes. High
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speed winds above the storm system push the ice crystals on ahead. When
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you see haloes around the sun or moon, you can be sure of two things-there
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are cirrostratus clounds above and, in a day or two, the skies will darken
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with an approaching storm.
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