Investigation of Dynamic/Thermodynamic Processes of Mountain/Valley Flow and Afternoon Thunderstorm System over Complex Terrain and Its Interaction with Land Surface Hydrologic Processes in Taiwan(Second Year)

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.