翻訳と辞書 Words near each other ・ Langmuir Laboratory for Atmospheric Research ・ Langmuir probe ・ Langmuir states ・ Langley Academy, Slough ・ Langley Aerodrome ・ Langley baronets ・ Langley Blaze ・ Langley Burrell ・ Langley Castle ・ Langley Centre ・ Langley Chapel ・ Langley Covered Bridge ・ Langley Creek ・ Langley Education Centre ・ Langley Events Centre ・ Langley extrapolation ・ Langley Field ・ Langley Fine Arts School ・ Langley Fork Historic District ・ Langley Fox Building Partnership v De Valence ・ Langley Frank Willard Smith ・ Langley Fundamental Secondary School ・ Langley Gold Medal ・ Langley Grammar School ・ Langley Green ・ Langley Green & West Green (electoral division) ・ Langley Green railway station ・ Langley Green, West Midlands ・ Langley Green, West Sussex ・ Langley Hall Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Langley extrapolation ： ウィキペディア英語版 Langley extrapolation Langley extrapolation is a method for determining the Sun's radiance at the top of the atmosphere with ground-based instrumentation, and is often used to remove the effect of the atmosphere from measurements of, for example, aerosol optical thickness or ozone. It is based on repeated measurements with a sun photometer operated at a given location for a cloudless morning or afternoon, as the Sun moves across the sky. It is named for American astronomer and physicist Samuel Pierpont Langley. ==Theory== It is known from Beer's law that, for every instantaneous measurement, the ''direct-Sun radiance'' ''I'' is linked to the ''solar extraterrestrial radiance'' ''I''0 and the atmospheric optical depth $\backslash tau$ by the following equation: where ''m'' is a geometrical factor accounting for the slant path through the atmosphere, known as the airmass factor. For a plane-parallel atmosphere, the airmass factor is simple to determine if one knows the solar zenith angle θ: ''m'' = 1/cos(θ). As time passes, the Sun moves across the sky, and therefore θ and ''m'' vary according to known astronomical laws. By taking the logarithm of the above equation, one obtains: and if one assumes that the atmospheric disturbance $\backslash tau$ does not change during the observations (which last for a morning or an afternoon), the plot of ln ''I'' versus ''m'' is a straight line with a slope equal to $\backslash tau$. Then, by linear extrapolation to ''m'' = 0, one obtains ''I''0, i.e. the Sun's radiance that would be observed by an instrument placed above the atmosphere. The requirement for good ''Langley plots'' is a constant atmosphere (constant $\backslash tau$). This requirement can be fulfilled only under particular conditions, since the atmosphere is continuously changing. Needed conditions are in particular: the absence of clouds along the optical path, and the absence of variations in the atmospheric aerosol layer. Since aerosols tend to be more concentrated at low altitude, Langley extrapolation is often performed at high mountain sites. Data from NASA Glenn Research Center indicates that the Langley plot accuracy is improved if the data is taken above the tropopause. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Langley extrapolation」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.