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| 題 名 | 中央氣象局動力區域氣候預報系統臺灣地區預報驗證技術之改進=Improved Validation Zoning Scheme for the Dynamically Downscaled Regional Climate Forecast System of CWB |
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| 作 者 | 蕭志惠; 陳世欽; 林原堂; | 書刊名 | 氣象學報 |
| 卷 期 | 52:2 2015.10[民104.10] |
| 頁 次 | 頁1-17 |
| 分類號 | 328.88 |
| 關鍵詞 | 動力降尺度; 4分區; 季預報; Dynamical downscaling; Zoning; Seasonal prediction; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 中央氣象局之動力區域氣候預測系統,係以美國國際氣候與社會研究院之全球大氣季節預報作為美國國家環境預報中心及中央氣象局的區域波譜模式之初始場及背景場,進行東亞地區 60公里水平解析度動力降尺度之季節預報。同時也針對臺灣地區,進行 4分區降水及二米溫度的三分類機率預報。初步分析顯示,本局預測系統分區預報之技術得分略優於氣候預報。為了更提高 4分區預報之分辨能力,本實驗以模式的陸點為基礎,重新定義各分區的模式網格點;測站方面則是選取臺灣本島除恆春、大武站外的 19站,重新進行分區。分析 2011年 1月至 2014年 12月的預報結果,與目前預測系統相比,陸點分區可提高北、南及東區的降水機率預報正確率,尤其是東區之年平均命中率可提高 1.46%。以季節來看,12月至 5月之預報命中率均獲得改善,其中又以 2月至 4月的提高最為顯著,整體而言對於春雨的預報能力能有相當大的幫助。雖然陸點分區預報會略降低二米溫度的預報命中率,但二米溫度的總平均預報命中率仍可達 36.3%。 |
| 英文摘要 | Using two Regional Spectral Models of the Central Weather Bureau (CWB) and the National Centers of Environmental Prediction, downscaled ECHAM global forecasts over East Asia were routinely casted for seasonal probability forecasts over Taiwan by CWB since 2003. Initial validations suggest that this dynamical downscaled forecast in precipitation and 2-m temperature is statistically superior to no-skill climatology forecasts. To further identify the forecast skill of the dynamically downscaled climate forecast system of CWB, we propose a new zoning scheme using only the model land grids (LG) to define 4 regions of Taiwan. The current operational zoning scheme (OP) not only shared a few land points among different regions, several ocean points were also included. For validation during a short period of January 2011 through December 2014, LG scheme significantly raised hit-rates of precipitation from using OP scheme for December to May over Taiwan’s northern, southern, and, especially, eastern regions. Although the monthly 2-meter temperature LG hit-rates, in comparison to that of OP, were slightly reduced or maintained at the same level for most of the year, the averaged hit-rates still reached 36.3% or better. |
本系統中英文摘要資訊取自各篇刊載內容。