本研究利用臺灣氣候變遷推估與資訊平台計畫 (TCCIP) 提供之再分析網格 降雨資料，分析1960-2015 年間臺灣夏季 (7-9 月) 大雨 (≧50 mm/day) 和豪雨 (≧200 mm/day) 發生頻率變化。主要大 (豪) 雨事件出現於5 月至9 月，當中又 以7-9 月的夏季發生頻率最高，日降雨量達50 毫米 (含) 的大雨事件和200 毫米 (含) 以上的豪雨事件發生頻率，分別占了年總發生頻率的50%和72%。從空間 分布來看，主要區域出現在嘉義至屏東山區、宜蘭南澳山地、雪山山脈與大屯火 山群等地。從年際變化來看，臺灣夏季大 (豪) 雨發生頻率變化，與該年受颱風 活動影響頻率高低關係密切，而大氣環流配置扮演重要角色。在大 (豪) 雨發生 頻率偏多年期間，西北太平洋副熱帶高壓脊線位置偏北，颱風往臺灣移動機率增 加，造成全臺大雨發生頻率明顯增加。偏少年期間則呈現相反結果，西北太平洋 副熱帶高壓西伸、高壓脊線位置偏南，颱風影響臺灣頻率降低。從長期變化來看， 2001-2008 年間是臺灣大 (豪) 雨發生頻率的高峰期，該時期大 (豪) 雨頻率增 加，主要即是受到颱風影響臺灣頻率增加所致，非颱風系統的貢獻度相對低。

This study utilizes the rainfall reanalysis dataset developed from Taiwan Climate Change Projection and Information Platform Project (TCCIP) to examine the changes of heavy (≧50 mm/day) and extremely heavy (≧200 mm/day) rainfall frequencies in Taiwan during the summer season (July to September). The major rainfall season in Taiwan generally occurs from May to September. However, about 50% of heavy and 72% of extremely heavy rainfall events occur between July and September. The spatial distribution analysis reveals that the main rainfall events take place between Chiayi and Pingtung, Nanao Mountain over the south of Yilan County, in the Hsuehshan Range and Tatun volcano group. For the inter-annual variation, analytical results identified that typhoons are highly correlated with the western North Pacific subtropical high (WNPSH) ridge behavior. The northward movement of the WNPSH ridge causes typhoons to slip toward Taiwan. When the typhoon approaches Taiwan, the typhoon-associated heavy and extremely heavy rainfalls significantly affect on the local area. In contrast, the southwestward extension of the WNPSH ridge decrease the impacts of typhoons on Taiwan. The increases in typhoon frequency during 2001–2008 result from significantly rising heavy and extremely heavy rainfall events over the long term.