此計畫延續前年度計畫書續提第二年計畫，主要研究目的為藉由高解析度氣象模擬以探討臺灣複雜山區環境，地表加熱作用對大氣熱、動力過程演變的影響。分析方法將探討 (1)綜觀環境場不明顯，台灣處於較為穩定的大氣條件，且有高污染事件的發生，來探討山谷風環流形成之熱動力過程，以及縱觀環境風場對台灣局部環流形成的影響，及後續如何影響污染物的傳輸過程;(2)當台灣處於不穩定的大氣環境，來探討山區環流結構以及午後熱對流系統形成機制。另外，午後熱對流常帶來大量降雨，甚至造成嚴重洪水問題。因此，抑規劃探討午後熱對流降雨系統，所產生之降雨量對地表水循環過程的影響，包含土壤溼度的變化以及地表、地底徑流過程，以及後續對水資源的應用討論。預計探討重點如下：(1) 台灣山區上下坡風、山谷風環流結構特性以及與海陸風環流結構之交互作用; (2) 台灣地區局部環流結構對污染物傳輸擴散的影響; (3)午後熱對流形成機制; (4) 午後熱對流降雨與地表水循環過程之交互作用。研究方法，將使用WRF氣象模式，來進行高解析度氣象模擬（<1公里）。而在地表水循環過程的探討，將使用Noah-MP (multi-parameterization options) 地表水文模式，來討論地表水循環的變化過程。由於Noah-MP地表模式考量了較複雜的地表水文循環過程，包含動態的地下水位變化(dynamically determined water table)以及側向水的排水過程(lateral flow)，這對模擬台灣複雜山區地形之地表水循環過程相當重要。且當模式模擬進入更高解析度時，台灣山高坡陡所形成的地下水傳送過程的模擬也顯得更為重要。我們預期此研究成果，將可提供在複雜山區環境，大氣熱、動力過程的發展機制，同時釐清台灣山區之地表加熱作用、環流結構特性、台灣中部地區局部環流如何影響當地污染物傳輸過程以及午後熱對流形成機制。並透過大氣與地表水文模式的結合，來瞭解午後熱對流系統對地表水循環過程之影響，及後續水資源的應用討論。 ;This proposal is the extension of the previous year’s project. The objective is to study the atmospheric dynamic/thermodynamic processes over the complex terrain in Taiwan and how it affects the mountain-valley wind structures and the afternoon-thunderstorm system. The analysis will focus on two different atmospheric environments: (1) Under the weak synoptic forcing, and the local air pollution can be accumulated due to the local flow patterns; (2) Under the unstable atmospheric condition, and the afternoon thunderstorm are likely to be formed. In addition, we will discuss the precipitation caused by the convective system and investigate its subsequent impact on the land surface hydrologic processes including the soil moisture variation and surface/subsurface runoff processes. The objectives of this proposal include: (1) investigations of the upslope/downslope and mountain/valley wind structures and its interaction with the land-sea breeze circulation; (2) study the relation between the local circulations and the air pollutants dispersions; (3) discussions of the afternoon thunderstorm formation mechanism; (4) study the impact of the convective precipitation on the land surface hydrological processes over the mountainous area. In this study, we will utilize the high resolution Weather Research and Forecasting (WRF) model to study the fine scale structures over the mountainous area. To study the land surface hydrologic processes, we will utilize Noah-MP (multi-parameterization options) land surface model (LSM). Unlike Noah LSM that only considers a free drainage lower boundary condition, the Noah-MP LSM considers the dynamically determined water table depth within the model soil layers and the lateral flow of the aquifer water, those processes are generally important over the complex terrain and on high- resolution model.We are expecting the results from this study should be able to provide a comprehensive understanding of the development of the atmospheric dynamic/thermodynamic processes over the complex topography, and to figure out the formation mechanisms of the mountain/valley wind structures and how the local circulation affects the air pollutants dispersion as well as the processes that leads to the formation of the afternoon thunderstorms over the mountainous area. The interaction between the convective precipitation and the land surface hydrologic processes will be discussed through the fine scale meteorological and land surface hydrologic modeling technique.
