| 摘要: | 大氣氣膠對太陽輻射的消光作用造成大氣冷卻和加溫，是影響地球環境變遷的重要污染物。氣膠消光係數是由散光係數和吸光係數所構成，因此，要準確評估大氣氣膠對太陽輻射光學效應必須仰賴正確的氣膠消光係數。本文以新莊微粒超級測站量測的氣膠消光係數來評估台北都會區氣膠光學特性，由於新莊微粒超級測站量測的氣膠消光係數沒有修正氣膠散光儀的光源照射積分角度，也沒有修正氣膠吸光儀的濾紙纖維多重散射及沉積在濾紙微粒的消光效應，因此，本文參考Anderson and Ogren (1998)和Colluad Coen et al. (2010)論文分別修正量測的氣膠散光和吸光係數。 研究結果顯示，修正後氣膠散光係數較修正前高15%，修正後氣膠吸光係數較修正前低8%，修正後氣膠消光係數較修正前高13%，直接受到影響的是單次散射反照率的增加，修正後單次散射反照率較修正前高3%。本文以修正後氣膠消光係數推估大氣氣膠光學尺度(scale height)，修正後也較修正前低約13%，顯示垂直空氣柱氣膠分布的實際高度較修正前低。 本文篩選中研院設置於台灣大學的光達有效數據， 比較2008~2009年間量測氣膠消光係數的垂直剖面變化，發現光學尺度呈現不同的季節變化與日變化，在春季時會有較高的光學尺度，主要是春季容易受大陸沙塵傳輸影響。最後，本文篩選沙塵時期、節慶日、PM2.5高濃度事件日與平常日，探討氣膠消光係數與光學尺度的變化。 It's important pollutants that affect the global environmental changes caused by atmospheric aerosol extinction of solar radiation can cooling and warming the atmospheric. The light extinction coefficient is the sum of the light scattering and light absorption coefficients, therefore, it's the correct atmospheric light extinction coefficient is needed for evaluation of aerosol effects on solar radiation. To assess the aerosol optical properties in Taipei metropolitan area, the aerosol extinction coefficient have been observed at Hsin-Chuang supersite station in Taipei, cause of the observed data didn't corrected for the truncation error and for the non-idealities in angular intensity distribution of the light and didn't took explicitly into account the fact that the filter-loading correction, the multiple scattering correction and the scattering correction. Therefore, the corrected methods are according to Anderson and Ogren (1998) and Colluad Coen et al. (2010). The study investigates the real aerosol scattering coefficient is higher than original value 15%, the real absorption coefficient is lower than original values 8% and the real extinction coefficient is higher than original value 13%, it directly affected is increase of single scattering albedo,(SSA), the real SSA is higher than original value 3%,meanwhile,the scale height is determined by aerosol extinction coefficient and aerosol optical depth, the real height is lower than 13%it represents the aerosol distribution height in vertical is lower than original height. This paper use LIDAR to measured the vertically resolved of extinction is co-owned by the Research Center for Environmental Change, Academia Sinica and the Department of Atmospheric Science, National Taiwan University in 2008~2009.The result found scale height have strong seasonal cycle and daily cycle, it's higher in spring, shows there are often Asian dust storms events during spring. This paper, now, investigate the change of aerosol extinction coefficient and scale height in dust storms events, festivals, PM2.5 high concentration events and normal days, respectively. |
