土地利用改變對區域強降雨的影響

Abstract

本研究主要的目的是利用 WRF 模式分析不同的土地利用資料對於模擬區域對流降雨事件的影響，氣象條件的選擇為有強對流潛勢且無大尺度系統的影響。在此利用了一個 Slab model，可以藉由觀測資料來估計混合層高度及舉升凝結高度，並對兩高度接觸時間與隨後的對流降雨事件做量化處理。此 Slab model 可用來幫助本研究判斷 WRF 模式所選用的個案作數值解析，以分辨隨後的降雨現象是否為對流降雨。在研究中耦合了 Urban canopy model 並測試了不同粗糙長度的敏感度。 模擬結果顯示使用不同的土地利用資料會有顯著的差異（如: 降雨、風速、地表溫度等），而在固定的範圍內，都市地區的土地利用資料所占比例越大會有較高的降雨量及地表溫度，水氣混合比則較少。

The major objective of this study is to utilize Weather Research and Forecasting (WRF) model to analyze the impact of different land use data on the regional convective rainfall events. The meteorological condition chosen for this analysis is to from the days with strong convective potential and no large scale system. In addition to the numerical model, in this study, a slab model coupled with observed data was utilized to estimate the dynamics of mixed layer (Zi) and lifting condensation level (LCL), and further quantify the onset of the subsequent convective precipitation events. Furthermore, this slab model was used to classify the precipitation events into convective and non-convective cases for the numerical analysis using WRF in this study. The study applies urban canopy model and tests the sensitivity of different roughness length. In different land use data, the simulation results indicate that there are significant differences in meteorological factors (ex. precipitation, wind speed, surface temperature…etc). In a fix range, the simulation result has higher surface temperature and rainfall but has lower water mixing ratio in the land use data which urban area is the majority.