| 摘要: | 本研究於2008/10/14 ~ 2009/04/30在鹿林山觀測氣膠、分析氣膠化學成分及檢索乾氣膠光學監測數據，研究目的是探討影響大氣氣膠含水量以及鹿林山乾氣膠光學係數的主要因子。 本研究以統計多元迴歸分析方法(N=37)發現大氣PM10氣膠含水量的影響因子，依照影響程度順序為未量測的氣膠成分(PM10, others)、氣膠硫酸根離子(SO42-)、氣膠鈣離子(Ca2+)、氣膠硝酸根離子(NO3-)以及氣膠水不可溶有機碳(WIOC)；PM10親水性水可溶有機氣膠只有在生質燃燒(BB)期間，對大氣氣膠含水量的影響較顯著。大氣PM2.5氣膠含水量的主要影響因子是水可溶有機碳(WSOC)和SO42-，兩者對大氣PM2.5氣膠含水量的影響相當。 生質燃燒長程傳輸氣膠會使鹿林山乾氣膠光學係數遠高於區域型測站，相對地，在非生質燃燒期間，鹿林山白天氣膠會受到谷風或亞洲大陸污染物傳送的影響。鹿林山氣膠各氣流軌跡來源，依污染嚴重性分別為生質燃燒期間來自源區和來自源區並經過中國南方，非生質燃燒期間來自亞洲大陸、海洋、源區並經過中國南方。鹿林山大氣氣膠在非生質燃燒期間，對於輻射作用力是降溫效應，但在生質燃燒期間，則相對會促進大氣暖化，因此對於環境變遷的影響是存在的。 鹿林山乾氣膠光學係數主要受到次微米氣膠影響，光學直徑粒徑範圍在0.10 ~ 0.26 μm和0.30 ~ 1.00 μm。此外，大部分的氣膠化學成分也都與光學直徑小於1 μm的細粒徑氣膠有很好相關。最後以統計多元迴歸分析探討乾氣膠光學係數影響因子(N=40)，發現依照氣膠成分濃度和迴歸係數乘積計算，影響順序為鉀離子、銨根離子以及NO3-。 This study collected atmospheric aerosols, analyzed aerosol chemical composition, and retrieved optical data of dry aerosols at Mt. Lulin from 14 October 2008 to 30 April 2009. The objectives are aimed at investigating major factors for aerosol water mass and optical coefficients of dry aerosol. Multiple regression analysis (N=37) shows that the order of importance for factors affecting PM10 water mass are unmeasured PM10 (PM10, others), sulfate ion (SO42-), calcium ion (Ca2+), nitrate ion (NO3-), and water-insoluble organic carbon (WIOC). Hydrophilic water-soluble organic carbon only shows its influence during biomass burning (BB) period. The major factors for PM2.5 water mass are water-soluble organic carbon (WSOC) and SO42-, both have equal significance. The level of optical coefficients was observed to elevate significantly above other regional stations when Mt. Lulin was influenced by transported BB plume. In contrast, daytime aerosol was affected by pollution from local valley wind or Asian continent during non-biomass burning (NBB) period. Based on backward trajectory analysis, as sorted by seriousness of pollution, air masses from BB source region either directly or via the southern China during BB periods were most polluted followed by that from Asia continent, oceanic area, and source region via the southern China during NBB periods. The aerosols observed at Mt. Lulin have cooling effect in radiative forcing during NBB period, while that of BB period show relative warming effect and thus more toward environmental change. Optical coefficients of dry aerosols are mainly affected by submicron aerosols with optical diameter ranged from 0.10 ~ 0.26 and 0.30 ~ 1.00 μm. In addition, most aerosol chemical components are correllated well with fine aerosols with optical diameter less than 1 μm. Finally, the regression analysis on optical coefficients of dry aerosol (N=40) shows that important aerosol components calculated by the product of their atmospheric concentrations and regression coefficients are potassium ion, ammonium ions, and NO3- accordingly. |
