Wang Chenxi, Yao Jianqun, Liang Xudong. The establishment and verification of the operational ensemble forecast system for Shanghai regional precipitation. J Appl Meteor Sci, 2007, 18(2): 173-180.
Citation: Wang Chenxi, Yao Jianqun, Liang Xudong. The establishment and verification of the operational ensemble forecast system for Shanghai regional precipitation. J Appl Meteor Sci, 2007, 18(2): 173-180.

The Establishment and Verification of the Operational Ensemble Forecast System for Shanghai Regional Precipitation

  • Received Date: 2005-12-19
  • Rev Recd Date: 2006-10-19
  • Publish Date: 2007-04-30
  • The operational ensemble forecast system for Shanghai regional precipitation is established. The model is based on MM5 in the system, with a one way two nesting procedure. The coarse grid domain of 101×101 grid points has a horizontal grid spacing of 45 km, while the inner grid domain of 70×70 grid points has a horizontal grid spacing of 15 km. Both domains have 21 vertical sigma levels. Eight different configurations of MM5 are used to produce an 8 member ensemble forecast. The approach to generating eight members is to use different convective parameterization schemes and different PBL parameterization schemes of the inner grid domain. In this system, all steps from data collection, data processing and model running to output automatically are carried out by computer. The system starts operating on August 1, 2005. The system operates twice everyday and each time it runs to 48 h forecast. The forecasts are then displayed on Website. Since the start of the operation, the system has shown stability and reliability. The forecasts from August to October are verified in the fields of ensemble mean, probabilistic forecast and spread. The results show the ensemble means of precipitations of low thresholds are more skillful than the ensemble means of precipitations of high thresholds. For precipitations of low thresholds, the larger the forecasting probability is, the larger the usefulness of probabilistic forecast is. For precipitations of high thresholds, the smaller the forecasting probability is, the larger the usefulness of probabilistic forecast is. The results also show the system has the problem of too small spread. In conclusion, the performance of the system is alright in forecasting precipitation. The precipitation forecasts of low thresholds seem better than the forecasts of high thresholds. The products of the system, especially the products of probability forecasts can be used as a reference. However, there are still some problems in the system, which should be improved in the future.
  • Fig. 1  ETSs of 0—24 h ensemble mean precipitation from 08:00 ensembles in August anDseptember of 2005 for four thresholds

    Fig. 2  ETSs of 0—24 h ensemble mean and each member precipitation from 08:00 ensemble in August of 2005 for the 10 mm threshold (a) and 25 mm threshold (b)

    Fig. 3  Skillful percent of 0—24 h and 24—48 h ensemble mean precipitation from 08:00 and 20:00 ensembles in August anDseptember of 2005 for four thresholds

    Fig. 4  ETSs of 0—24 h and 24—48 h precipitation probability from 08:00 and 20:00 ensembles in August of 2005 for the 0.1 mm threshold (a), 10 mm threshold (b), 25 mm threshold (c) and 50 mm threshold (d)

    Fig. 5  Skillful percent of 0—24 h and 24—48 h precipitation probability from 08:00 and 20:00 ensembles in August of 2005 for the 0.1 mm threshold (a), 10 mm threshold (b), 25 mm threshold (c) and 50 mm threshold (d)

    Fig. 6  D/Ds of 0—24 h and 24—48 h precipitation from 08:00 and 20:00 ensembles in August and October of 2005

    Fig. 7  Talagrand diagrams of 0—24 h and 24 — 48 h precipitation from 08:00 and 20:00 ensembles in August and October of 2005

    Table  1  The formation of ensemble members of the system

  • [1]
    Toth Z, Kalnay E.Ensemble forecasting at NCEP and the breeding method.Mon Wea Rev, 1997, 125:3297-3319. doi:  10.1175/1520-0493(1997)125<3297:EFANAT>2.0.CO;2
    [2]
    Hersbach H, Mureau R, Opsteegh J D, et al.A short-range ensemble prediction system for the European area.Mon Wea Rev, 2000, 128:3501-3519. doi:  10.1175/1520-0493(2000)128<3501:ASRTEM>2.0.CO;2
    [3]
    Mullen S L, Buizza R.Quantitative precipitation forecasts over the United States by the ECMWF ensemble prediction system.Mon Wea Rev, 2001, 129:638-663. doi:  10.1175/1520-0493(2001)129<0638:QPFOTU>2.0.CO;2
    [4]
    Wandishin M S, Mullen S L, Stensrud D J, et al.Evaluation of a short-range multimodel ensemble system.Mon Wea Rev, 2001, 129:729-747. doi:  10.1175/1520-0493(2001)129<0729:EOASRM>2.0.CO;2
    [5]
    李泽椿, 陈德辉.国家气象中心集合数值预报业务系统的发展及应用.应用气象学报, 2002, 13(1):1-15. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20020101&flag=1
    [6]
    王晨稀.短期降水集合预报中随机扰动和增长模繁殖初值生成法的比较试验.气象学报, 2002, 60(增刊):119-126. http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGQX201510023159.htm
    [7]
    王晨稀, 端义宏.短期集合预报技术在梅雨降水预报中的试验研究.应用气象学报, 2003, 14(1):69-78. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20030108&flag=1
    [8]
    陈静, 薛纪善, 颜宏.华南中尺度暴雨数值预报的不确定性与集合预报试验.气象学报, 2003, 61(4):432-446. doi:  10.11676/qxxb2003.042
    [9]
    王晨稀.短期集合降水概率预报试验.应用气象学报, 2005, 16(1):79-88. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20050110&flag=1
    [10]
    周霞琼, 端义宏, 朱永禔.应用集合预报产品开展热带气旋路径概率预报试验.气象学报, 2002, 60(增刊):111-118. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX201404015.htm
    [11]
    周霞琼, 端义宏, 朱永禔.热带气旋路径集合预报方法研究Ⅰ--正压模式结果的初步分析.热带气象学报, 2003, 19(1):1-8. http://www.cnki.com.cn/Article/CJFDTOTAL-RDQX200301000.htm
    [12]
    周霞琼, 张秀珍, 端义宏, 等.滞后平均法 (LAF) 在热带气旋路径集合预报中的应用.气象科学, 2003, 23(4):410-417. http://www.cnki.com.cn/Article/CJFDTOTAL-QXKX200304003.htm
    [13]
    陈静, 薛纪善, 颜宏.物理过程参数化方案对中尺度暴雨数值模拟影响的研究.气象学报, 2003, 61(2):203-218. doi:  10.11676/qxxb2003.019
    [14]
    Talagrand O, Vautard R.Evaluation of Probabilistic Prediction Systems.Workshop on Predictability ECMWF, 1997. http://citeseerx.ist.psu.edu/showciting?cid=2767911
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    • Received : 2005-12-19
    • Accepted : 2006-10-19
    • Published : 2007-04-30

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