近年來的觀測與數值模擬研究已經顯示地形降水的複雜度，以及突顯我們對它瞭解 的不足。綜觀環境的多樣化、地形地貌及對流(或熱力)引發的環流皆會顯著改變地形降 水的物理過程。而山區附近詳細觀測資料的缺乏也是長久以來我們無法深入探討地形降 水的主因。臺灣是一個多山的島嶼，豪雨的發生經常與地形效應密切相關。因此，增進 臺灣地區地形降水機制的了解，是一項克不容緩的重要議題。 本研究計畫主要的科學目的在於藉著地形附近所收集的高解析度都卜勒雷達資料 與降雨觀測資料，針對不同環境條件來詳細檢視地形效應對降水分佈及強度的影響，以 期增進我們對於臺灣地形降水過程的瞭解。而研究內容將特別著重於弱綜觀與颱風環境 下之地形降水觀測與分析。除此之外，本計畫也將利用較理想化的地形降水估計診斷模 式，評估其對於臺灣地形降水的掌握能力，以提供未來降水估計研究與降雨預報的參考。 Recent observational and numerical studies have revealed the complexity of orographic precipitation and a significant gap in our knowledge of its underlying processes. Many factors, such as the variable synoptic environments, orographic geometries and the influences of convectively/thermodynamically generated circulations, can influence the physical processes of orographic precipitation. The lack of detailed observations over the mountainous regions often causes difficulties in documenting these phenomena. For mountainous Taiwan, the occurrence of the torrential rainfall is usually related to the topographic effects. To achieve a better prediction of heavy rainfall in Taiwan, improving understanding of mechanisms of orographic precipitation under different environmental conditions is critically important. In this study, the detailed Doppler radar observations collected from the Taiwan area are used to investigate how orographic effects influence the precipitation distribution and intensity in different environmental conditions, in an attempt to explore our knowledge of precipitation processes active over mountains. Study on the orographic precipitation occurring in two distinct environments (i.e., weakly synoptic conditions vs. typhoon environment) will be particularly focused. In addition, we will also develop and evaluate an idealized diagnosis model of orographic precipitation, and these research results are expected to provide important references to future studies of precipitation estimate and forecasting in the Taiwan area.
