查詢結果分析
來源資料
頁籤選單縮合
題 名 | 臺灣地區颱風降水估計校驗=An Evaluation of Estimation of Typhoon Rainfall in the Region of Taiwan |
---|---|
作 者 | 王惠民; 吳石吉; 葉天降; | 書刊名 | 氣象學報 |
卷 期 | 48:2 2010.09[民99.09] |
頁 次 | 頁1-12 |
分類號 | 328.63 |
關鍵詞 | 雨量推估法; 最佳路徑; Method of typhoon rainfall amount estimation; Best track; |
語 文 | 中文(Chinese) |
中文摘要 | 本文使用1998-2006年間,中央氣象局265個雨量自動觀測站和25個人工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),針對颱風地面中心在東經118–126度、北緯19–28度範圍內的颱風降水個案,分5–6月、7–8月和9–10月3個 期間,以及豪雨(平均時雨量大於5.4毫米)和非豪雨2類,發展3、6及12小時颱風雨量推估法,並以2007-2008年間自動觀測站和人工觀測站之時雨量資料作預報校驗。比較平均法、持續法及雨量推估法預報之平均絕對誤差在空間分布的情形,以及平均法和雨量推估法相對於持續法的預報改善率。 校驗結果顯示,在颱風雨量估計之平均絕對誤差方面:3小時預報平均絕對誤差,以雨量推估法最大預報誤差值在9至15毫米左右分布區域最小表現最佳;以平均法分布區域最大表現最差。3種方法共同的特徵是較大預報誤差均出現在蘇澳至花蓮一帶山區、雪山及大雪山山區和阿里山至高雄一帶山區。6小時預報平均絕對誤差,3種方法最大預報誤差值之空間分布特徵與3小時預報誤差相似,誤差值多在20至30毫米左右;以雨量推估法分布區 域較小表現最好,持續法分布區域最大表現最差。12小時預報平均絕對誤差,3種方法最大預報誤差之空間分布特徵與6小時預報誤差相似,但持續法及雨量推估法範圍較6小時預報擴大,其中又以持續法預報平均絕對誤差在40至60毫米左右的區域最大表現最差;以平均法區域最小表現最好。相對於持續法之預報改善率方面:雨量推估法3小時及6小時預報改善率在0至20%的區域明顯大於平均法。但12小時預報改善率在20%至40%的區域,平均法明顯大於雨量推估法。因此,雨量推估法3及6小時預報改善率優於平均法,但平均法12小時預報優於雨量推估法。 |
英文摘要 | In this paper, the data of hourly rainfall amount of CWB 265 auto-raingauge stations and the 25 surface observation stations and the JTWC best tracks of typhoons in every 6 hours during the period of 1998 through 2006 were used to develop the method of 3-h, 6-h, and 12-h typhoon rainfall amount estimations by dividing all the cases of the surface centers of typhoon in the domain of 118-126 degree of longitude and 19-28 degree of latitude into two categories of extremely heavy rainfall (average hourly rainfall greater than 5.4 mm/hr) and non-extremely heavy rainfall and in three periods of May-June, and July-August, and September- October. The data of hourly rainfall amount of the auto-raingauge stations and surface observation stations during the period of 2007 through 2008 were used to verify the forecasting and compare the spacial distribution of mean absolute errors of forecasting among the method of climatological mean, the method of persistence, and the method of typhoon rainfall amount estimation. And the improvement ratios for the method of climatological mean and the method of typhoon rainfall amount estimation with respect to the method of persistence were also calculated. The results of evaluation revealed, in the mean absolute errors of typhoon rainfall amount estimation, the performance of the method of typhoon rainfall amount estimation in 3-h projection was the best because that its regions of the greatest forecasting error in the range of 9 mm through 15 mm were the minimum, and the method of climatological mean was the worst. The characteristics in common for the three methods were the greater forecasting errors occurred in the regions of the mountain area from Su-ao to Hualien, Xueshan to Daxueshan, and Alishan to Kaohsiung. For the mean absolute errors of 6-h projection, the three methods had similar characteristics in spacial distribution with greatest forecasting errors of 3-h projection. The greatest mean absolute errors in 6-h projection for the three methods were between 20mm and 30mm and the performance of the method of typhoon rainfall amount estimation was the best, and the method of persistence was the worst. For the mean absolute errors of 12-h projection, the characteristics of special distribution of the greatest forecasting errors were similar as 6-h projection, but the regions for the methods of persistence and typhoon rainfall amount estimation were broader than in 6-h projections. The performance of the method of persistence in 12-h projection was the worst for that its regions of the greatest forecasting error in the range of 40 mm through 60 mm were the maximum and the method of climatological mean was the best. For the improvement ratio over the method of persistence, the regions of the improvement ratio in the range of 0% through 20% of the method of typhoon rainfall amount estimation for 3-h and 6-h projections were broader than of the method of climatological mean. But the regions of the improvement ratio in the range of 20% through 40% of the method of climatological mean for 12-h projection were broader than of the method of typhoon rainfall amount estimation. Therefore, the improvement ratios for the method of typhoon rainfall amount estimation in 3-h and 6-h projections were superior to the method of climatological mean, but it was better for the method of climatological mean in 12-h projection. |
本系統中英文摘要資訊取自各篇刊載內容。