• 作者： 陳景森; 廖文祥
• 作者服務機構： 中央大學大氣物理系
• 中文摘要： 台灣地區由於地形複雜，許多大氣現象是氣流與地形相互作用所產生的。欲深入研究這些現象，必須借助三維、非靜力有地形座標的數值模式。現在我們在台灣地區已成功發展出第一個這種型式（但不含水汽）的模式。驗証模式是以氣流在低福勞數（Froude number）的環境下通過鐘型地形所產生的大氣現象來檢驗的。模擬結果顯示，山後有一對渦漩而山前有逆流現象。這種結果與Smolarkiewicz和Rotunno（1989, 1990）結果符合，因而加強我們對模式的信心。同時我們也發現，山後渦漩是否產生與山高和山之寬度的比例有關。如果比例太低，即山很平滑，則無此現象。另外環境風若隨高度順時針偏向時，山後只剩下順時針的渦漩。 我們同時以較真實的台灣地形，在沒有環境風的情形下讓地面加熱，則地面氣流向山頂輻合，而較大的上升運動在山頂及較陡的斜坡區發生。往後的工作是一方面著重於分析上述氣流與地形作用所產生的大氣現象的動力原因，另一方面擴展模式成為包含水汽的濕模式。
• 英文摘要： We have established the first version of a dry, non-hydrostatic, three-dimensional numerical modelof a terrain-following system to study atmospheric phenomena in Taiwan. The model was tested againstan airflow passing a bell-shaped mountain at a low Froude number. Simulation results showed that a pairof lee vortices formed and upwind reverse flow occurred just as Smolarkiewicz and Rotunno (1989, 1990)found. We also found that the ratio of mountain height to mountain width could affect the formation ofa lee vortex If this ratio was too small, no lee vortex formed. When an upstream wind veered with height,then only one lee cyclonic vortex remained. A more realistic topography of Taiwan was also used for the model where surface heating was appliedto a calm environment. Airflow moved toward mountain tops with larger vertical velocity occurring nearmountain peaks and steeper slope areas. These regions had larger temperature gradients along the topographyThe simulation result under the influence of a south-south-west wind and surface heating was similar to thatfrom the observation data. A model which includes the moisturizing process is under development.
• 中文關鍵字： non-hydrostatic model; terrain effect; lee vortex; surface heating
• 英文關鍵字： --