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題 名 | 豪大雨之頻率分析方法=Statistical Analysis of Heavy Rainfall Frequency |
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作 者 | 盧孟明; 陳佳正; | 書刊名 | 氣象學報 |
卷 期 | 46:1 民94.12 |
頁 次 | 頁45-59 |
分類號 | 328.63 |
關鍵詞 | 水文氣候; 極端降雨頻率分析; 氣候異常; Hydro-climatology; Heavy rainfall frequency analysis; Climate extremes; |
語 文 | 中文(Chinese) |
中文摘要 | 本文嘗試提出一種探討極端天氣與氣候關係的客觀方法,並且以實例說明極端降雨事件氣候意義的詮釋是建立在如何擷取觀測資料和選用統計機率分布模擬樣本母體的基礎上。以氣象局定義的四種豪大雨等級為例,藉每年24小時累積雨量極大值組成的樣本空間推估的廣義極端值分布(GEV distribution)比使用全部日雨量資料推估的指數分布(Exponential distribution)更適於估計各測站不同等級的豪大雨之發生頻率或重現期距。按GEV推估的「大雨」(50mm/24hr)重現期距幾近於1年,表示屬於氣候上經常發生的事件。「豪雨」(130mm/24hr)和「大雨」的重現期距只有些微差距,都在1年左右。「大豪雨」(200mm/24hr)重現期距在臺北較長(約2.9年),在花蓮較短(1.3年),而「超大豪雨」(350mm/24hr)重現期距在臺北約有14年,花蓮為5.1年,期距範圍符合經驗上對嚴重洪災發生頻率的預期。因水文氣候的地域性差異,建議未來豪大雨分級或許可依水文氣候的分區設計更可反應區域性氣候特徵的標準。 |
英文摘要 | In this study, we demonstrate how heavy rainfall frequency estimation can be affected by the strategy of data sampling and the selection of probability distribution functions. The hourly rainfall data during the period of 1951-2004 at five Taiwan stations are analyzed. The results suggest that the General Extreme Value (GEV) distribution is suitable for modeling the heavy rainfall events in Taiwan. The return periods of four heavy rainfall categories defined by the Central Weather Bureau are estimated based on the GEV distribution. The return periods of both Category-1 (heavy rain, rain rate ≧ 50mm/24hr) and Category-2 (extremely heavy rain, rain rate ≧ 130mm/24hr) rainfall events are about 1 year. The Category-3 (torrential rain, rain rate ≧ 200mm/24h) rainfall events have the return periods of about 1-3 years depending on where the station is located. The Category-4 (extremely torrential rain, rain rate ≧ 350mm/24hr) rainfall events have the return periods of about 5-14 years. The distinct differences in the return periods between different stations strongly suggest the necessity of taking the hydro-climate characteristics of each station into account when defining heavy rainfall categories to be used for flood disaster prevention. |
本系統中英文摘要資訊取自各篇刊載內容。