- 期刊
- OpenAccess
對流允許模式模擬中尺度對流系統降水個案之研究
Study on the precipitation event for the Mesoscale Convective System with a Convection-Permitting Model
摘要
2021年5月30日鋒面通過臺灣地區，受伴隨生成的中尺度對流系統影響，臺灣西半部地區多數測站出現豪雨等級之降雨量，並造成淹水災情。當日臺灣地區低層（850-700 hPa）伴隨之低層噴流將南海暖濕空氣輸送臺灣地區，供應對流系統能量來源；500 hPa顯示有槽線接近臺灣地區，有利上升運動，可見該日綜觀環境場提供了有利中尺度對流系統生成之條件。本研究使用WRF模式，並以對流允許模式研究2021年5月30日中尺度對流系統個案，以了解WRF在高解析度模式下模擬個案之表現。模擬結果顯示，豪雨模擬位置與實際觀測大致相符且Threat Score、Bias Score與Fraction Skill Score顯示，模式對於豪雨具有預報能力。
並列摘要
When Mei-yu fronts passed through Taiwan on 30 May 2021, mesoscale convective system (MCS) formed and developed, which affected Taiwan afterwards. The MCS produced heavy rainfall over the west regions of Taiwan including many meteorological stations, up to the standard of extremely heavy rain. It also caused severe floods in many areas. The strong low-level jet at the 850-700 hPa layer in Taiwan area bringing warm moist air to Taiwan from South China Sea provided the moisture and energy for the convective systems. The trough lines was approaching Taiwan at 500 hPa, and there was a strong divergence and obvious ascending motion at these upper levels of the atmosphere, which was a more conducive environment for the growth of MSC. For evaluating the performance of rainfall prediction for MCS in Taiwan, Weather Research and Forecast (WRF) Model with Convection-Permitting Models was carried out in this study. The result shows that the simulation of extremely heavy rain is close to the spot of observation and its skillful for extremely heavy rain through 3 skill scores (Threat Score; Bias Score; Fraction Skill Score).