摘要
混合層高度為估計空氣污染潛勢和濃度的重要參數，其代表污染物向上擴散所能到達之最大高度，但僅利用一天兩次的例行探空觀測要準確的預測逐時混合層高度有其難度，因此本研究以能量守衡方程式及紊流動能方程式為基礎，發展出一套考量較多氣象參數之混合層預測式。 為了解此預測式之可行性及準確度，本研究針對台北、台中、高雄及高屏地區作混合層高度值的模擬，並將模擬結果與實際觀測值、CALMET氣象模組及光化學軌跡模式(TPAQM)輸出結果作比對，結果顯示均有0.80以上之高相關性；但與TPAQM計算結果間有明顯的高估或低估現象，此為Holzworth method無法考量溫度平流效應對混合層發展之影響及探空資料空間解析度不足所致；而在空間分布上，本模式所計算的混合層高度場相較於TPAQM在海陸分布上有較明顯的分野，且更能夠顯示出內陸地區混合層高度的日變化。 研究中進一步將所計算之通風指數與汙染物監測濃度作比對以了解其相互關係，結果顯示當高污染事件發生時，通風指數確實有明顯之下降，不利於污染物之擴散。 本文亦針對混合層預測式所需輸入之各參數進行敏感度分析，結果顯示Bowen Ratio為影響混合層發展最顯著的地表參數，而混合層上方位溫斜率值對於混合層高度的發展亦有相當程度之影響。
並列摘要
Mixing layer height (MH) is an important parameter for estimating the potential and concentrations of air pollution. It stands for the highest height of pollutants diffused upward. However, it is difficult to predict hourly MH precisely only by twice upper air measurements one day. Therefore, this study is based on thermodynamic equations and kinetic energy equations of turbulence in order to develop a series of MH prediction equations with more meteorological parameters. For understanding the workability and precision of these prediction equations, at first this study not only simulates the MHs of Taipei, Taichung, Kaoshung cities and Kao-ping area but also compares these results with meteorological models of CLAMET and TPAQM. And the comparisons show the high correlation (up to 0.8) between them. When the results of MH prediction equations model are compared with TPAQM, they get higher or lower values than TPAQM. The reasons are that Holzworth method can not concern about the warm and cold advections effect and the upper air data used do not get enough finer space-spread. About the results spread on the domain of my model, they show more different MH fields between the land and the sea around and get more sharply change of the land MHs on daytime than TPAQM. Secondly, it gets ventilation index and air pollution monitoring value together to find the relationship of them. The results of it presents that when serious air pollution episode happens, the ventilation index actually decreases and the pollutants are diffused weakly. At last, this study also takes the sensitivity analyses of input parameters for the prediction equations. The result shows that Bowen Ratio is the most influencing surface parameter for the development of the MH and the same with the potential temperature lapse rate in the layer above mixing height.