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| 題 名 | 臺灣地區颱風極端時降雨之特徵分析=An Analysis on the Characteristics of Extreme Hourly Rainfall of Typhoon over Taiwan |
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| 作 者 | 王惠民; 葉天降; | 書刊名 | 氣象學報 |
| 卷 期 | 48:3 2011.09[民100.09] |
| 頁 次 | 頁1-13 |
| 分類號 | 328.63 |
| 關鍵詞 | 颱風; 門檻值; 極端時降雨; Typhoon; Threshold; Extreme hourly rainfall; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 本文使用19982008年間,中央氣象局265個雨量自動觀測站和25個地 面觀測站之時雨量資料及美軍聯合颱風警報中心(Joint Typhoon Warning Center)6小時1次之颱風最佳路徑(best track)為分析資料。選取當颱風地面中 心在東經118–126度、北緯19–28度範圍內,中央氣象局290個雨量觀測站之 任一測站時雨量大於(含)15毫米時,同一時間所有測站之時雨量個案,利用 百分排序法,取各測站百分排序前百分之一的最小時雨量值,作為各地颱風 極端時降雨之門檻值。分析颱風極端時雨量發生地和颱風地面中心之相對位 置與及其頻率在不同時期於臺灣地區分布之特徵。 滿足前述時間與颱風所在位置條件之個案有1996筆,依前述極端時降 雨門檻值之定義,即為1996筆時雨量由大而小排序後之最前面第20個個案 之時雨量值。分析結果顯示,颱風極端時降雨約90%是發生在距颱風地面 中心2.5經緯度半徑內,其中5-6月極端時降雨發生的頻率遠低於7-10月。 7-8月期間極端時降雨發生頻率較高的地區從中部日月潭山區向南延伸至高 屏山區並包括嘉義、高雄及屏東地區,這種分布特徵可能與夏季西南季風 有關。9-10月期間極端時降雨發生頻率較高的地區大都分布於新竹、花蓮以 北,這種分布特徵可能與冬季東北季風有關。另外,7-10月各地發生極端時 降雨後持續於未來1小時發生極端時降雨的機會偏高,但隨著時間增加,發 生極端時降雨的機會明顯減低。 |
| 英文摘要 | In this paper, the data of hourly rainfall amount of 265 automatic raingauge stations and 25 surface weather stations of the Central Weather Bureau and the best tracks of typhoons in every 6 hours of Joint Typhoon Warning Center during the period of 1998 through 2008 were used as the analysis data. All the hourly rainfall data at all stations would be selected at the same time when the hourly rainfall value exceeded or equaled to 15 mm at one of the 290 observation stations of Central Weather Bureau, when the surface centers of typhoon were in the domain of 118-126 degrees of longitude and 19-28 degrees of latitude. After ranking all the selected cases and then taking the first value above 99th percentile of each station to be the threshold value of extreme hourly rainfall for every station, the occurrence locations of extreme hourly rainfall relative to surface centers of typhoons and the characteristics of its distribution of occurrence frequency over Taiwan can be analyzed. There were 1996 cases satisfying the conditions of time and locations of typhoon centers mentioned above. According to the previous definition of threshold value of extreme hourly rainfall, it was the 20th highest value of hourly rainfall case after ranking the 1996 cases from high to low. The results revealed that 90% occurrence locations of extreme hourly rainfall were in the region with radius of 2.5 degrees from typhoon centers, and the occurrence frequency of extreme hourly rainfall in May and June was much lower than in July through October. In July and August, the regions with higher occurrence frequency of extreme hourly rainfall extended southward from the central mountain area around SunMoon lake to the mountain areas in Kaohsiung and Pingtung including Chiayi, Kaohsiung, and Pingtung. The characteristics of distribution might be associated with the summer southwesterly monsoon. In September and October, most of the regions with higher occurrence frequency of extreme hourly rainfall were in the northern regions in Hsinchu and Hualien. The characteristics of distribution might be associated with the winter northeasterly monsoon. In addition, the occurrence probability of extreme hourly rainfall in the next hour after extreme hourly rainfall occurred was high during the period of July through October. But it decreased obviously as time increased. |
本系統中英文摘要資訊取自各篇刊載內容。