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標題: | 高雄都會區氣膠吸濕特性之探討 A study of hygroscopicity for urban aerosols in Kaohsiung |
作者: | Chia-Hung Hsu 徐嘉鴻 |
指導教授: | 洪惠敏(Hui-Ming Hung) |
關鍵字: | 雲凝結核,吸溼參數,氣膠, cloud condensation nuclei,hygroscopic parameter,aerosol, |
出版年 : | 2015 |
學位: | 碩士 |
摘要: | 氣膠的吸溼能力在大氣中扮演重要的角色,它會影響氣膠成雲,進而影響整個生活環境及氣候系統。本研究在2013年的1月和7月利用雲凝結核計數器(CCNc),凝結核計數器(CPC)以及掃描式電移動度微粒分徑器(SMPS)在高雄都會區量測氣膠的活化率(NCCN/NCN)和粒徑分布,並根據活化粒徑(DA)和過飽和度(SS),進而推算吸溼參數(κ)。除了探討當地氣膠吸溼能力的特性外,也和其他台灣地區的量測結果做一比較及討論。
高雄冬季和夏季的平均觀測結果可以看到氣膠老化的特徵,也就是隨著粒徑增加(60-200nm),氣膠的吸溼參數有跟著增加(冬天:0.15-0.21,夏天:0.08-0.23)。冬季的觀測可以由氣象條件和氣團來源分成4個時期。1/18前後由台灣北部移入的氣團可以量測到最高的吸溼參數為0.27-0.54。同樣由台中外海移入的氣團,也會因為當地的風速大小使氣膠有不同的吸溼性,1/23-24的平均風速為1.73m/s,吸溼參數為0.10-0.15;1/25-26的平均風速為2.05m/s,吸溼參數為0.15-0.34。夏季的觀測可以分成平日時期和颱風時期,颱風時期的吸溼參數較高且並無規律變化。平日時期的氣膠吸溼參數有明顯的日變化,推測氣膠吸溼性的減少可能和汽機車排放有關,氣膠的吸溼性增加則和大氣化學反應以及當地的風速增加有關。 台灣郊區的氣膠吸溼性平均而言都比都會區還來得佳,可能和汽機車排放以及郊區的氣膠特性有關。在都會區之中以夏季的高雄都會區有最佳的吸溼性,台北(κ=0.02-0.12)和台中(κ=0.04-0.14)都會區則較低。在高雄都會區又以冬季的氣膠的吸溼性優於夏季。 Hygroscopicity of aerosol played an important role in the atmosphere. It would influent human life and climate system by acting as cloud condensation nuclei to affect cloud formation. In this study, we measured the activation ratios (NCCN/NCN) and the aerosol number size distribution using a cloud condensation nuclei counter (CCNc), condensation particle counter (CPC) and a scanning mobility particle sizer system (SMPS). The critical diameter (Dc) for a given supersaturation (SS) was estimated. The (SS, Dc) datasets were applied to derive the single hygroscopic parameter (κ). We discussed κ of aerosol, when measured in January and July 2013 in Kaohsiung city. And we focused on hygroscopicity variation for other sites. Both Kaohsiung city winter and summer κ increased from 0.15 to 0.21 and from 0.08 to 0.23 meanly, exhibited a string size dependence in the ranging of 60 nm to 200 nm. Based on the weather condition and back trajectory analysis, winter observation was divided into 4 periods. 1/18 measured highest κ (0.27-0.54) where air parcel from north of Taiwan. Local wind speed would change κ, although the air parcel from same place. Both air parcels from sea beside Taichung, 1/23-24 measured lower mean wind speed (1.73m/s) and lower κ (0.10-0.15), and 1/25-26 measured higher mean wind speed (2.05m/s) and higher κ (0.15-0.34). Summer observation was divided into 2 periods, normal and typhoon. Latter period measured higher κ and irregular trend. Normal period showed a significant diurnal variation. It was likely that soot from vehicle coagulated and decreased κ, and then atmospheric chemical reaction and local wind speed increased κ. Hygroscopicity of country aerosol was higher than urban in Taiwan. It was likely that soot from vehicle coagulated and decreased κ in cities, and then environment of countries increased κ. Hygroscopicity in Kaohsiung city was greater than Taipei city (κ=0.02-0.12) and Taichung city (κ=0.04-0.14) in summer. For seasonal variation, κ of winter was better than summer in Kaohsiung city. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/55234 |
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顯示於系所單位: | 大氣科學系 |
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