查詢結果分析
來源資料
頁籤選單縮合
題 名 | 民國90年NFS模式之颱風路徑與定量降水預報校驗=The Evaluation of Typhoon Track and Quantitative Precipitation Forecasts of CWB's NFS in 2001 |
---|---|
作 者 | 洪景山; | 書刊名 | 氣象學報 |
卷 期 | 44:4 2002.12[民91.12] |
頁 次 | 頁41-53 |
分類號 | 328.888 |
關鍵詞 | 颱風路徑預報; 颱風定量降水預報; Typhoon track forecast; Typhoon QPF; NFS; |
語 文 | 中文(Chinese) |
中文摘要 | 本文以民國90年中央氣象局發布颱風警報的9個颱風中的8個颱風(不含潭美颱風),針就中央氣象局非靜力預報系統(Nonhydrostatic Forecast System,NFS)45公里網格解析度進行路徑預報和定量降水預報校驗。NFS颱風路徑預報24小時平均誤差約175(174)公里,48小時約27l(232)公里,72小時則為523(410)公里(括號內為不含海燕和潭美颱風)。分析顯示當模擬的颱風進入高緯度後均產生較大的速度誤差,顯示模式無法正確模擬出颱風和中緯度系統之交互作用過程。此外,NFS初始颱風定位誤差達76公里,這主要是因為NFS初始猜測場來自較粗解析度的全球模式分析場所致。因此,如果在NFS中植入颱風渦旋,不僅可以掌握較理想的颱風結構,也可以改善初始定位誤差,這對提高路徑預報能力應可有顯著的助益。定量降水預報方面,除了0-12小時的降水預報外,模式所預測的降水次數均比實際發生的降水次數多;這可能和模式的降水過程以及較粗模式解析度有關,因此改進模式的降水參數法應可以有效地改善颱風的定量降水預報。公正預兆得分顯示,0-12小時預報的降水技術得分最高,而隨著預報時間增加,技術得分也隨之減少。當雨量閥值在20~50mm/12hr之間時有較好的得分,但對於大於50mm/12hr的大雨預報能力則相當有限。 |
英文摘要 | This paper evaluated the performance for the typhoon track and quantitative precipitation forecast (QPF) of the 45-km mesh of the Non-hydrostatic Forecast System (NFS) of the Central Weather Bureau (CWB) in 2001. A total of 9 typhoon cases were evaluated. The averaged forecast track error for 8 cases (excluding typhoon Trami) was 175 (174) km for 24-hr, 271 (232) km for 48-hr, and 523 (410) km tot 72-hr forecast (numbers in the parentheses indicated excluding typhoon Haiyen). The NFS model had large track error as the typhoon interacted with the mid-latitude systems. Because of the initial typhoon circulation was interpolated from the coarse grid of the global model, the position of the modeling typhoon center had an error of 76 kin. Thus, improving the bogus process in NFS will greatly improve the track forecast. In addition, the model over-predicted precipitations as increasing the forecast time. That might be related to the impropriate cumulus parameterization scheme used in NFS (Kuo scheme). The ETS score showed that the forecast skill decreased as increasing the forecast time. The rain rate threshold between 20-50 mm/12 hr had the most skillful QPF; however, there were little skill when larger than 50 mm/12 hr. |
本系統中英文摘要資訊取自各篇刊載內容。