| DC 欄位 |
值 |
語言 |
| DC.contributor | 大氣物理研究所 | zh_TW |
| DC.creator | 蔣至剛 | zh_TW |
| DC.creator | Chih-Kang Chiang | en_US |
| dc.date.accessioned | 2010-7-29T07:39:07Z | |
| dc.date.available | 2010-7-29T07:39:07Z | |
| dc.date.issued | 2010 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=93641002 | |
| dc.contributor.department | 大氣物理研究所 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 隨著中國的工業化與經濟發展，中國之空氣污染物排放量持續增加，也使東亞污染出流可能增加其污染程度。北台灣地區正處於東亞污染出流影響之鄰近下風地區。因此，欲探討北台灣地區臭氧污染之成因，臭氧濃度來源分析是相當重要的一項工作。本研究藉由1994-2005年超過10年之臭氧濃度長期資料分析及2003年全年之臭氧濃度長期模擬，量化與具體說明北台灣地區臭氧污染之季節效應與東亞污染出流之影響。由12年之北台灣地區臭氧濃度發生頻率分析顯示，其濃度分佈有顯著之季節差異，尤其是春季與夏季。此外，介於40-60ppb之臭氧濃度發生頻率於12年間各季皆約有超過ㄧ倍的頻率增加，大於100ppb之臭氧濃度發生頻率則無顯著變化。如此說明，北台灣地區中低濃度與高濃度之臭氧可能有其不同的來源及受到季節效應之影響。
由2003年之CMAQ全年臭氧模擬結果顯示，模式對於不同之地理區位與季節差異其模擬結果皆有相當的代表性。就臭氧濃度之量值模擬上，整體而言以北台灣地區五個具不同地理區位特性之測站結果分析顯示，其模擬誤差在-7%至15%之範圍內，依不同的模擬情境而定。模擬結果也同時說明，與那國島與恆春測站具有區域性臭氧背景濃度分佈之代表性。
由基準模擬案例與控制模擬案例之模擬結果相互比較顯示，北台灣地區之臭氧濃度來源可分為三種型態。1.強烈受當地污染源支配之型態(型態一)。2.受東亞污染出流氣團直接影響之型態(型態二)。3.東亞污染出流臭氧濃度墊高北台灣週遭區域之環境背景並伴隨當地污染產生高臭氧事件之型態(型態三)。型態一多發生於部分春季與大多數之夏季，臭氧濃度有強烈之日夜變化，且多有高臭氧事件日發生。型態二常發生於綜觀天氣系統在北台灣週遭為北或東北風之情況，風速高(>5m/s)並伴隨強勁東亞出流氣團於邊界層內之影響，臭氧污染入流直接影響之濃度範圍為50-100ppb。型態三常發生於春季、冬末及初秋，其臭氧濃度加成效果約有20%，受加成影響之臭氧濃度垂直分佈可達2000公尺。
綜合顯示，東亞污染出流臭氧對北台灣地區之臭氧濃度影響在<100ppb之各濃度分層皆有相當比例的影響，其影響多由一波波氣團的型式到達北台灣地區，如此也說明北台灣地區12年臭氧濃度頻率變化，”東亞污染出流之臭氧濃度”將扮演相當重要的關鍵角色。另一方面，>100ppb之臭氧濃度多由本地污染所貢獻，東亞污染出流臭氧之影響小於10%，然而此影響將可能使臭氧濃度超過小時120ppb之法規標準。在型態三之情況下，春季將有75%的站日數改變，使臭氧濃度由未及法規標準至超過法規標準，夏季則為31%之站日數改變。就季節效應而言，東亞污染出流對北台灣地區春季臭氧濃度影響最大，平均而言有超過30%之影響，對夏季影響最小，低於15%。這也說明，季節差異將是研究北台灣地區臭氧污染相當重要的分類依據。
| zh_TW |
| dc.description.abstract | Northern Taiwan is in the downwind neighboring area of East Asia so that pollutant outflow from East Asia will have direct impact on the ozone mixing ratio in Taiwan. In a coupled study with long-term ozone observations and one year, CMAQ, regional-scale Chemical Transport Model (CTM) simulations we obtained an understanding of the transport and chemical processes governing seasonal ozone variations and provided quantified estimates of the impact of the outflow.
We simulated the ozone evolution over Taiwan for one year in 2003. Model results show that it is quite capable in capturing the behavior of ozone observation at different locations. Overall, the error of CMAQ simulation result of ozone mixing ratio is less than 15%, ranging from -7% to 14% for five important stations although the standard deviations can be larger. We found that the Hung-Chen and Yonagunijima stations can represent the characteristic behavior of regional-scale background ozone variation near Taiwan.
By comparing the simulations with and without East Asia anthropogenic emissions, we found that the variation of ozone mixing ratio in northern Taiwan can be divided into three types: 1. local pollution strongly influences the ozone mixing ratio; 2. significant direct impact on northern Taiwan ozone mixing ratio from Asian continental outflow; 3. Asian continental outflow enhance the mixing ratio of background ozone leading to high ozone episode days in northern Taiwan. Type 1 always happened on local high ozone episodes with wind speeds less than 3 m/s and the wind direction generally from the east or southwest. Type 2 always happened under the influence of East China high pressure systems with dominant wind from the northeast to northern Taiwan and accompanying surface wind speeds greater than 5 m/s and result in the direct impact of having ozone mixing ratio of 50-100 ppb. Type 3 always happened in the spring, late winter and earlier autumn. The background ozone in northern Taiwan will have up to 20% incremental increase from the impact of Asian continental outflow and the vertical distribution of ozone can be affected up to 2000m height.
Our findings suggest that for the study period high oxidant formation in northern Taiwan is predominantly due to local pollution. However, under type 3 condition, the enhanced ozone mixing ratio over the 1-hr 120ppb ozone regulation limit occurred 52 station days (75% of the total occurrences) in northern Taiwan in the springtime and 23 station days (31% of the total occurrences) in the summer. On the other hand, seasonal variation of ozone mixing ratio over northern Taiwan can be affected by east Asian outflow from around 30% in springtime to less than 15% in the summer.
| en_US |
| DC.subject | 臭氧汙染季節效應 | zh_TW |
| DC.subject | 汙染物長程傳送 | zh_TW |
| DC.subject | 東亞汙染出流臭氧 | zh_TW |
| DC.subject | Ozone pollution | en_US |
| DC.subject | Ozone long-range transport | en_US |
| DC.subject | Asian continental ouflow | en_US |
| DC.title | 北台灣地區臭氧汙染之季節效應與東亞汙染出流之影響 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Seasonal Effect and the Impact of Asian Continental Outflow on Ozone Mixing Ratio in Northern Taiwan | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |