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|Title: ||Long-term wintertime cloud water chemistry observed at Mt. Bamboo in Taiwan: Overall characteristics and impact of biomass burning|
|Authors: ||裴秋水;Thuy, Bui Thu|
|Issue Date: ||2017-10-27 12:27:42 (UTC+8)|
|Abstract: ||本研究探究北台灣竹子山 (25.18oN, 121.53oE; 1,100 m MSL) 1996-2016年於東北季風季受亞洲大陸長程傳輸影響時候之雲霧水化學。雲霧水為每小時採樣，每個樣本會分析其pH值及無機水溶性離子。在觀測之20年期間，共採得180個雲事件，5480個雲霧水樣本。雲事件及混合事件(同時有雲霧及降雨)的pH值中位數分別為4.0及4.4。|
雲霧水離子之主要成份為海鹽離子(Na+, Cl-) 及非海鹽硫酸根 (nss-SO42-)，可能與氣團來自於亞洲大陸有關。Nss-SO42- 隨時間有下降的趨勢，可能與中國有效控制SO2之排放有關。
;This study investigated long-term chemistry of cloud water at Mt. Bamboo (25.18oN, 121.53oE; 1,100 m MSL) in northern Taiwan under primary influence of Asian continental outflows during northeast monsoon seasons, in 1996-2016. Cloud water was collected on an hourly basis. Samples were measured with pH and inorganic soluble ions were analyzed. In total, 180 cloud events were observed with 5,480 samples collected. Long-term median pH values are 4.0 and 4.4 for cloud samples and mixed (cloud and rain at the same time) samples, respectively. Major contributors in cloud water were sea-salt components (Na+, Cl-) and nss (non sea-salt)-SO42- which might be associated with Asian continental outflow. Nss-SO42- concentration showed a significant decreasing trend over time, which was probably attributed to SO2 emission reduction in China.
Relationship between source and receptor was studied by using trajectory cluster analysis. Although northern China is a greater source region comparing to central China and Indochina, ion cloud loading of air mass coming from northern China cluster region show lower values than those from central China and Indochina cluster regions, suggesting that transport pathway’s role may override source emission’s.
Two cases with extremely cloud events observed were studied using a combination of backward trajectory, remote sensing tools and meteorology data. The case of 2002/03/22-24 evidenced a vertical mixing of 2 polluted cloud layers (lower layer includes Asian anthropogenic species and dust; upper layer includes biomass burning species). The case of 2016/01/18-23 depicted a polluted cloud period corresponding to a strong influence from Asian continental outflow, followed by a clean cloud period due to the rain-out effect.
It was also found that biomass burning aerosol from Indochina can impact the site during sampling periods due to the air mass subsidence via pressure high. However, impact was rarely observed (10 cases over 1996-2016).
|Appears in Collections:||[大氣物理研究所 ] 博碩士論文|
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