颱風對台灣地區造成的威脅甚大,但由於受到地形、颱風路徑與其結構的影響,不同颱風造成的損失以及受災之地區並不相同。2004年中有三個颱風影響台灣地區,造成嚴重損失,其中敏督利颱風在中心過後台灣地區後全台下大雨,艾利颱風之颱風眼未登陸台灣卻造成北台灣嚴重水患,而南瑪都颱風在台灣南部登陸,經台東出海,卻造成花蓮布洛灣、天祥等山區降下豪大雨,以上的颱風降雨均與台灣地形關係密切。本研究針對此三個颱風降雨時空分布進行分析探討,並用衛星雲圖資料做進一步研究,以確實了解此三個颱風在台灣造成地區性大雨的原因。研究結果發現敏都利颱風於2004年7月2日00至06UTC間中心通過淡水河口,所引進的西南氣流,帶來豪雨。艾利颱風中心眼於2004年8月24至25日間同樣通過淡水河口之北方後,並向西行進,呈「西北颱」特徵,颱風環流的西北氣流與地形夾角甚大,造成豪大雨。至於南瑪都颱風,中心先通過菲島北部,而後轉東北移動,掃過恆春半島後續向東北而去,是有紀錄以來12月份第一個在台灣登陸的颱風,且當時有大陸冷高壓南侵,因共伴效應產生的副低壓導致北部地區雨量較大,而天祥一帶小區域豪雨則由於地地形與颱風雲系產生交互作用而導致對流加強產生豪大雨。
Typhoon is a very dangerous weather system .There are at least 2 to3 typhoon to hit Taiwan island per year , during 2004 there are three typhoons invaded Taiwan that caused flash flood serious damage .
The topographic structure of Taiwan island is very special where Central Mountain Range (CMR) run from north to south , as typhoon near Taiwan island , the circulation of typhoon encounters CMR the flow were blocked and upward motion , which will enhanced the convective cloud , that induced heavy rainfall in Taiwan area .
In this study satellite images and radar echo was analyzed , the result show that caused flash flood by that three typhoons , Midulle ,Aere, Nanmadol in Taiwan area has different reasons . For typhoon Midulle , as the center crossed Taiwan island and induced southwest flow generated heavy rainfall on Taiwan area . For typhoon Aere heavy rainfall in northern Taiwan area was caused by the northwest flow of its circulation. Typhoon Nanmadol , it was the first one landed Taiwan area in December , it is the local terrain effect caused Ha area heavy rainfall .
From the above analysis , some effort can be used that will benefit for the practical work .