西北太平洋（WNP）颱風生成數（NTC）具有年代際變化的現象，而颱風的生成會受大尺度環境場的影響，前人依此關係發展出颱風生成指數（GPI），但無法掌握到NTC年代際變化現象。因此本研究以Murakami and Wang（2010）的 GPI 及Wang and Murakami（2020）DGPI 指數中的環境參數為基礎，利用高解析度CMIP6 HighResMIP 資料與主成分迴歸分析（PCR），發展出能掌握在 WNP 區 NTC 年代際變化的 GPI 。
本研究發現，夏季時多數模式能模擬到 NTC 年代際變化的現象，但在 TC 突變的模擬上和觀測結果並不一致。秋季時，海氣耦合模式的年代際變化、突變模擬上比大氣模式好。模式中以 HadGEM3-GC31-HM 的海氣模式結果與觀測最接近。在兩時期 TC 生成的空間分布差異上，大氣模式的分布和觀測不符甚至相反，而海氣模式在TC多的位置與觀測相符，不過對活躍期數量較少的西北區域較無法掌握。在相關性分析結果上，海氣模式的結果也比大氣模式接近觀測值，且呈現正相關，大氣模式則為負相關。
藉由探討 NTC 變化與大尺度環境變化的關係，我們發現在活躍期，有利於 TC 生成的大尺度環境分布情況，會與自身 TC 生成較多的區域相對應。兩時期生成指數差異的結果顯示，觀測上 Murakami and Wang（2010）的 GPI 總值變化與實際的 NTC 變化相反，未能掌握非活躍期 NTC 大幅減少的特徵。
本研究發展的新 GPI 指數（NGPI），雖然選取的環境參數與原有的 GPI 接近，但大多數以年代際變化明顯的 PC2 、 PC3 居多，尤其是在夏季。 NGPI 與原 GPI 最大的不同是，夏天 NGPI 沒有絕對或相對渦度項，在動力因素上，只採用ω項、垂直風切項；在熱力因素上，只採用相對濕度 PC2 、 PC3 。秋天的 NGPI ，在動力因素上，則選用相對渦度項和垂直風切項，在熱力因素上，只採用相對濕度 PC1 。因此，在建立年代際變化新的 GPI 時，考慮不同季節選用不同的環境參數，對於不同季節 NTC 年代際變化的掌握會更好。

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