本研究使用IBM_VDRAS分析2021年11月26日的強降雨個案，搭配宜蘭強降雨實驗觀測，可辨識降雨四階段：階段一對流沿雪山山脈發展，向東北移動；階段二對流由西南側山谷肇始，聚集於中央山脈北段迎風側；階段三，平原北側系統消散，南方降雨系統開始東移；階段四，內陸降雨亦趨緩，沿海對流維持。比對由IBM_VDRAS所模擬結果，亦與降雨觀測相符，並與剖風儀、地面測站與微型探空進行校驗，結果指出此模式具有一定程度可分析冬季強降水。 持續調查宜蘭冬季降水的過程，發現個案中底層東北風增強與其強風軸位置，會影響平原環流結構；中層強勁西南風使對流胞往東北方移動，並挾帶水氣跨越山脈進入平原；陡峭雪山山脈有利於垂直渦漩建立，影響對流胞發展；中央山脈北段處於迎風側，產生地形效應使氣塊抬升而成雲致雨。另外，局地高壓的出現與位置，影響了降雨分布。綜上所述，透過IBM_VDRAS的動力、熱力以及微物理過程，可以清楚的調查宜蘭冬季強降水的演變與特徵。;Using IBM_VDRAS to analysis a heavy rainfall event on 26 November 2021 with the observations in YESR (Yilan Experiment Severe Rainfall), this study identified four stages of precipitation. The precipitation was located along the SMR (Snow Mountain Range) in Stage 1, began to develop in the NCMR (Northern Central Mountain Range) and expanded northeastward into the plain in Stage 2, and then as the precipitation decreased over the northern plain, the rain band began to move to the east side of the NCMR in Stage 3, and finally the systems dissipated over the interior and only coastal convection existed in Stage 4. The simulation results were validated against wind profiler, surface sites and storm tracker, demonstrating the ability to capture the features in this case. The research also investigated the features of this case, the results showed that the increasing low-level northeasterly wind would affect the circulation over the plain, the strong mid-level southwesterly wind make convection move northeastward and carry moisture into the plain, the steep Snow Mountain Range helps to establish the vertical vortices influenced the development of cells, and the northern Central Mountain Range captures the moisture transported by prevailing wind which induces the convection due to terrain effect. In addition, the local high-pressure systems play a key role in the location of the precipitation hotspot. From the kinematic, thermodynamic and microphysical fields of IBM_VDRAS, this study can clearly describe the evolution and characteristics of the winter heavy rainfall in Yilan.
