2023-01-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/701328目前最先進的全球大氣模式在模擬對流日夜變化現象仍有明顯偏差，尤其是在熱帶與季風區域有複雜地形的島嶼。本團隊針對台灣受地形鎖定午後雷雨的過往研究成果顯示，海陸山谷風局地環流傳送邊界層內高濕靜能，山區組織性對流發展整體具有對流深厚入流混和的特徵。近年台灣進行的數次氣象觀測實驗，曾在多點同時施放 ST 迷你探空儀，有效觀測到複雜地形附近的局地環流與邊界層濕靜能傳送。本計畫目標是結合 ST 密集觀測實驗與高解析度(dx≤500m)模擬來探討阿里山-曾文水庫山區午後對流的深厚入流結構。第一年會先分析 TaiwanVVM 真實地形大渦系集模擬結果，根據深厚入流的機率分布，選定西南平原至山腳的可能地點進行五天的預實驗，測試不同的施放策略。第二年進行第一次正式密集觀測，選定適合局地環流發展的夏季天氣型態，在海岸至山腳之間以三個移動或固定點位進行七天的連續 ST 施放。也會設計海-平原-山脈的理想地形進行大渦模擬，藉此推廣簡化局地環流提供山區熱對流深厚入流的概念。第三年進行第二次密集觀測，選定與第一次綜觀型態相似但背景環境條件(如西南風厚度、風速、中層水氣)有差異的時期觀測深厚入流，並搭配理想地形實驗的敏感性測試，討論背景環境對深厚入流與山區熱對流的影響。 The diurnal cycle of convection remains under-represented by current state-of-the-art global atmospheric models, particularly over islands in the Tropics and monsoon regions with complex topography. Our past and ongoing studies suggest that the development of the orographically-locked afternoon thunderstorms over the mountains of Taiwan exhibit the feature of deep-inflow mixing of convection, to which the local circulation (i.e., land-sea-mountain-valley breezes) transporting high moist static energy (MSE) from the boundary layer. Filed campaigns in recent years over Taiwan demonstrated that the “storm tracker” (ST) mini-radiosonde sensor can be applied to effectively observe local circulation and MSE transport in the boundary layer at multiple sites near the complex terrain. This study aims to apply intensive ST field observations and high-resolution (dx≤500m) simulations to investigate the deep inflow associated with afternoon convection over the Alishan-Tseng Wen reservoir region. In the first year, 5-day pilot observations with ST will be conducted to evaluate the potential sites over the southwestern plain and foothill areas, based on the locations with a high probability of deep inflow identified from the TaiwanVVM large-eddy simulation (LES) ensembles with realistic Taiwan topography. Different ST deployment strategies will also be tested and compared to capture the structure of the deep inflow In the second year, the first phase of intensive observations will be carried out for 7 days during the summertime weather regime that favors the development of local circulations. ST will be released at three mobile and/or stationary sites to cover the structure of deep inflow from the coast to the foothill. We will also design and perform LES with idealized ocean-plain-mountain topography to generalize the concept of local circulation serving as deep inflow to mountain diurnal convection. The deep inflow structure will be compared among the field observations, TaiwanVVM realistic topography simulations, and idealized topography simulations. In the third year, the second phase of intensive observation will be conducted. We will select a similar synoptic weather regime as in the first phase but specifically target variations in background conditions such as the thickness/intensity of southwesterly or mid-level moisture. Companion sensitivity simulations with idealized topography will also be carried out with different background conditions, to discuss their influences on the deep inflow and orographically-locked convection.對流日夜變化;深厚入流混和;邊界層過程;複雜地形;組織性對流;Diurnal Cycle of Convection; Deep Inflow Mixing; Boundary Layer Process; Complex Topography; Organized Convection