司东, 丁一汇, 柳艳菊. 2009: 全球海气耦合模式(BCC_CM1.0)对江淮梅雨降水预报的检验. 气象学报, (6): 947-960. DOI: 10.11676/qxxb2009.092
引用本文: 司东, 丁一汇, 柳艳菊. 2009: 全球海气耦合模式(BCC_CM1.0)对江淮梅雨降水预报的检验. 气象学报, (6): 947-960. DOI: 10.11676/qxxb2009.092
SI Dong, DING Yihui, LIU Yanju. 2009: Evaluation of Meiyu prediction in the Yangtze-Huaihe region by coupled Ocean-Atmosphere General Circulation Model (BCC_CM1.0). Acta Meteorologica Sinica, (6): 947-960. DOI: 10.11676/qxxb2009.092
Citation: SI Dong, DING Yihui, LIU Yanju. 2009: Evaluation of Meiyu prediction in the Yangtze-Huaihe region by coupled Ocean-Atmosphere General Circulation Model (BCC_CM1.0). Acta Meteorologica Sinica, (6): 947-960. DOI: 10.11676/qxxb2009.092

全球海气耦合模式(BCC_CM1.0)对江淮梅雨降水预报的检验

Evaluation of Meiyu prediction in the Yangtze-Huaihe region by coupled Ocean-Atmosphere General Circulation Model (BCC_CM1.0)

  • 摘要: 以国家气候中心全球大气海洋耦合模式(BCC-CM1.0)20 年的预报产品为基础,重点分 析了该模式对中国江淮梅雨的预报能力以及梅雨预报中存在误差的可能原因。试验表明:BC C-CM1.0对江淮梅雨降水有一定的预报能力,模式基本上能够预报出气候态下梅雨降水的 空间分布特征。尽管其方差贡献率和时间系数与观测相比有偏差,但模式还是能够预报出梅 雨降水的主要模态。气候平均下,BCC-CM1.0模式预报的梅雨雨带位置偏北,因而预报的 江淮流域长江以北降水偏多,而长江以南预报的降水偏少。同时发现模式对江淮流域梅雨期 中等强度降水预报较好,雨强概率分布与观测结果基本一致,而对大雨强降水和小雨强降水 预报相对较差。合成分析发现,江淮流域雨带偏北、降水偏少时,模式的预报能力较好;而 江淮流域雨带偏南、降水偏多时,模式预报能力相对较差。 BCC-CM1.0对高度场的预报普遍偏低,尤其是在青藏高原上空有一个虚假的低值中心,对 副热带高压的预报也偏弱,这样使得东亚季风区气压梯度增加,从而导致预报的东亚夏季风 偏强、向北推进的幅度加大,最终致使预报的梅雨雨带偏北。此外,比湿场预报的偏差也可 能是造成梅雨雨带偏北的原因之一。

     

    Abstract: Based on the output data of Coupled OceanAtmosphere General Circulation Model (BCC-CM1.0) of National Climate Center, the meiyu in the YangtzeHuaihe regio n ensemble prediction experiment is performed to verify the prediction ability o f the BCC-CM1.0 from 1978-2006. The results show that BCC-CM1.0 can predict the basic meiyu spatial pattern and the leading EOF mode. The predicted rain bel t is obviously north than the observation, so it causes more precipitation to th e north of the Yangtze River and predicts less precipitation to the south of the Yangtze River. Additionally, it shows that the medium intensity meiyu rainfall has been forecasted better than the high and low intensity rainfall. Synthetic a nalysis shows that BCC -CM1.0 can forecast the difference of meiyu rainfall bet ween meiyu forecasting good years and meiyu forecasting poor years, it has good performance when rain belt locates north and meiyu rainfall less; otherwise the model performs poorly. Geopotential height field forecasted by BCC-CM1.0 is substantially weaker t han the observation, especially in the QinghaiTibet Plateau and Western Pacifi c Subtropical High region, which causes barometric gradient over East Asian mons oon areas increasing and East Asian monsoon enhancing, therefore, enhanced East Asian monsoon maybe one reason that results in moving northward of rain belt in YangtzeHuaihe area in BCC-CM1.0. Furthermore, poor forecasting of moisture c ontent may also contribute to moving northward of rain belt in the YangtzeHuai he region.

     

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