气团[Airmass] - 达人(其实～我是卧底，来自外星)

2004/10/28 | 气团[Airmass]
类别(¤〖天文〗) | 评论(0) | 阅读(65) | 发表于 13:40: A measure of the height of atmosphere through which an observation is being made. For a plane parallel atmosphere,
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where is the latitude, is the declination, and HA is the hour angle.For an exponential spherical atmosphere
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at a radius R from the center and scale height H,the optical path (ignoring atmospheric refraction ) is
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(Young 1976). Dropping the term in the numerato and the term in the denominator gives
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Using Gradshteyn and Ryzhik (1965, p. 315) then gives
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where erfc function is the complementary error function. An approximation for moderately large
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is
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(Young 1976), which gives
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for the Earth. A correction for atmospheric refraction can be obtained by taking
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