宜蘭地區自古以多雨聞名，特別是在每年秋季，台灣西南部已進入枯水期， 位於東北部的宜蘭卻可能出現致災性降雨，造成當地生命財產蒙受極大的損失， 這些秋季豪雨的發生經常和共伴效應有關。本文比較蘇澳、宜蘭和竹子湖氣象站 在1982-2016年間的雨量觀測數據，指出蘇澳氣象站的豪雨紀錄是台灣秋季共伴 豪雨的代表性資料。透過該站及宜蘭縣境內自動測站秋季共伴豪雨事件所對應的 共伴颱風性質，本文嘗試框畫出台灣發生共伴降雨時的共伴颱風熱區，大致是在 15-23°N，108-124°E之間的區域。而由共伴豪雨事件與赤道太平洋地區聖嬰-南方 震盪(ENSO)活動紀錄的比對，證實兩者之間存在著遙相關。自1982年以來，在 反聖嬰現象發生期間的秋季，宜蘭地區往往也留下共伴豪雨紀錄，尤其是在強烈 反聖嬰事件期間。因為在赤道太平洋進入反聖嬰時期的秋季，有較多颱風的移動 路徑向西直行經過台灣南方海域，這將有利於共伴效應的發生，進而在宜蘭或台 灣北部、東北部地區降下共伴豪雨。這樣的結果不僅對氣象預測提供了極為重要 的訊息，在古氣候與古人文研究上，也提供了有關宜蘭古代豪雨事件的發生機制 與理論基礎。

In Taiwan, Yilan County is famous for its high precipitation, especially in seasons when the winter monsoon prevails. In particular, the interaction between tropical cyclones and northeasterly winds during autumn brings torrential rain and causes great damage and severe economic loss in Yilan. This study examined extremely heavy rain data (daily rainfall >200 mm) from the Suao, Yilan, and Jhuzihhu stations of the Taiwan Central Weather Bureau (CWB) during the period of 1982-2016. The finding suggests that Suao's records are more effective in representing the heavy rainfalls associated with the interaction between typhoons and the winter monsoon that occurs in autumn. Typhoon tracks corresponding to the extremely heavy rainfall in autumns recorded in Yilan County reveal a concentrated area of typhoons at 15-23°N, 108-124°E, while extremely heavy rainfalls occurred over northeastern Taiwan. In addition, the heavy autumn rainfall associated with the interaction between typhoons and the East Asia winter monsoon were observed to be closely related to El Nino-Southern Oscillation (ENSO) activity. They occurred significantly more frequently during cold episodes (La Nina) in the equatorial Pacific Ocean as compared to those that occurred during warm (El Nino) and normal episodes. Our findings indicate the useful predictability of seasonal forecasts of extremely heavy rain in autumn over northeastern Taiwan. On the other hand, the results show the relationship between ENSO regimes and extreme precipitation events in Yilan, which support the physical basis on paleoclimate proxy records, for example, the floods that occurred around 2000 years ago.