本計畫將從年際、十年際、到全球氣候變遷尺度的觀點，利用Yu et al.(2009)發展之颱風活躍度量度方法，重新檢視控制西北太平洋地區颱風活動之氣候條件（如：季風槽、太平洋副高、跨赤道氣流、哈德里胞等）和物理因子（如：大氣穩定度、垂直風切、渦度等）。本計畫也將利用對流準平衡理論，建立颱風活躍度和物理因子之關係，發展一個適合西北太平洋地區之「生成潛在指數」（genesis potential index），以作為未來颱風季節預報之基礎。
In this project, a new algorithm designed to measure the seasonal tropical cyclone (TC) activity developed by Yu et al (2009) is employed to reexamine the climate circulation changes (e.g., monsoon trough, subtropical high, cross-equatorial flows, and local Hadley circulation, etc.) and likely physical factors (e.g., atmospheric stability, vertical wind shear, vorticity, etc.) that control TC variability over the western North Pacific (WNP) region, with a focus on the interannual, interdecadal, and global warming time scales. The convective quasi-equilibrium assumption is employed to establish a robust relation between the physical factors and the seasonal TC activity. A new “genesis potential index” specifically designed for the WNP region is also proposed to provide a basis for the forecast of seasonal TC activity.
