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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/73864

    Title: 利用系集法估計與檢驗對流尺度之預報誤差:SoWMEX IOP8 個案分析
    Authors: 陳立昕;Chen, Li-Hsin
    Contributors: 大氣科學學系
    Keywords: 預報誤差協方差;中尺度對流系統;Forecast Error Covariance;Mesoscale Convective Systems
    Date: 2017-08-23
    Issue Date: 2017-10-27 12:27:55 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 本研究採用系集法(Ensemble-based method),首次在台灣藉由天氣個案模擬,針對
    對流尺度之預報誤差結構進行分析,個案選取 2008 年西南氣流聯合觀測實驗
    (SoWMEX IOP8)期間,於 06 月 15 至 16 日之間生成之中尺度對流系統(Mesoscale
    Convective Systems, MCSs),使用 WRF 單向巢狀網格,高解析度(3-km)之網格涵蓋台
    灣本島與台灣海峽,以及部分巴士海峽。以 72 組系集預報結果作為樣本,運用統計方
    法估算出背景(預報)誤差協方差(Background Error Covariance),其提供我們瞭解系集卡
    在 MCSs 影響期間,比較不同解析度(9, 3-km)之誤差結構,顯示高解析度的方差
    程(moist processes)產生;此外,降雨過程產生的冷池影響近地表溫度的方差。本研究
    溫度與垂直速度之正相關結構與潛熱釋放有關,低層之水平風 U 與 V,在台灣西南部
    估,期望能夠提供資料同化有利的策略,進而改進台灣地區雷達資料同化能力。;This study focus on the short-term forecast error structures with different resolution (9/
    3 km) at meso- and convective scales. With a set of 72-member ensemble forecasts by
    Weather Research and Forecasting (WRF) model, the error covariances are presented. A case
    study during Southwest Monsoon Experiment intensive observing period 8 (SoWMEX-IOP8)
    in 2008 is investigated. The characteristics of forecast error covariances are examined by the
    spread and error correlation in state variables.
    Compared with different resolution, the variance of state variables are larger in higher
    resolution, particularly in vertical velocity. It indicates higher resolution run (3-km) can
    better-represent the smaller scale uncertainties in this severe weather event. The time-series
    of ensemble spread reveal that significant variances are associated with the strength of rainfall
    rate. In the magnitude of horizontal wind, multi-scale interactions are found over the
    southwesterly flow region. The temperature near surface has relatively large quantity of
    variance in association with cold pool performances. Moist processes not only impact on the
    distribution of variance, but paly important role of error correlation in temporal and spatial
    structure. The cross correlation of the temperature and vertical velocity is strongly positive at
    high level dominated by latent heat release. The negative cross correlation between zonal and
    meridional wind over southwest quadrant of Taiwan illustrates the range affected by
    orography. The information of forecast error provides optimal strategies of data assimilation,
    especially for assimilating radar network over Taiwan area.
    Appears in Collections:[大氣物理研究所 ] 博碩士論文

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