甘玉婷,陈昊明,李建. 2021. 千米尺度数值预报模式对泰山地区暖季降水预报性能的评估. 气象学报,79(5):750-768. DOI: 10.11676/qxxb2021.055
引用本文: 甘玉婷,陈昊明,李建. 2021. 千米尺度数值预报模式对泰山地区暖季降水预报性能的评估. 气象学报,79(5):750-768. DOI: 10.11676/qxxb2021.055
Gan Yuting, Chen Haoming, Li Jian. 2021. Evaluation of the performance of kilometer scale numerical operation forecast model for warm season precipitation forecasting in Taishan region. Acta Meteorologica Sinica, 79(5):750-768. DOI: 10.11676/qxxb2021.055
Citation: Gan Yuting, Chen Haoming, Li Jian. 2021. Evaluation of the performance of kilometer scale numerical operation forecast model for warm season precipitation forecasting in Taishan region. Acta Meteorologica Sinica, 79(5):750-768. DOI: 10.11676/qxxb2021.055

千米尺度数值预报模式对泰山地区暖季降水预报性能的评估

Evaluation of the performance of kilometer scale numerical operation forecast model for warm season precipitation forecasting in Taishan region

  • 摘要: 为深入认识对流可分辨模式对小尺度孤立地形区降水的预报性能,使用2017年暖季(5—9月)台站逐时降水观测数据,以小时尺度降水特征为指标,细致评估了千米尺度分辨率(3 km)的北京“睿图”短期数值预报子系统(RMAPS-ST)对泰山及其周边地区降水特征的预报能力,并对比了不同起报时次(北京时08时和20时)的预报差异。评估发现,RMAPS-ST可以再现泰山站的局地降水中心,但区域西南侧降水预报小于观测,而泰山站及其东北侧则相反。清晨和午后时段的降水预报与观测相比存在较大偏差。以泰山站为例,RMAPS-ST易于低估夜间至清晨时段的降水频率,这可能与模式对降水系统发展演变过程的预报偏差以及清晨泰山站弱降水事件的漏报有关;清晨泰山站降水强度的预报在不同起报时次的结果中存在差异,20时起报存在大幅度高估的问题,进而导致其暖季平均降水量预报大于观测,而08时起报对于清晨降水强度的高估不明显;08时起报易高估泰山站午后的降水频率,这与其午后短历时降水事件数预报偏多有关,模式对山区热动力场的预报偏差是午后降水空报的可能原因。小时尺度降水特征已应用于中国气象局区域数值预报模式的业务评估体系中,本研究结果也表明,此类评估有助于深入认识千米尺度数值预报模式对降水日内变化的预报能力,从而为精细化降水产品的订正提供更详实的科学依据。

     

    Abstract: In order to further understand the performance of convection-permitting models for precipitation forecast in isolated, small-scale topographic regions, the precipitation forecast products of RMAPS-ST operational system at 3 km horizontal resolution are thoroughly evaluated against hourly precipitation data collected at 80 stations of National Meteorological Surface Observation Network in the Mountain Tai area during the warm season (May to September) of 2017. The evaluation is based on hourly precipitation characteristics and differences between rainfall forecasts starting at 20:00 BT and 08:00 BT are compared. The results of this study show that RMAPS-ST can reproduce the spatial distribution characteristics of hourly precipitation in the study area, but the forecast rainfall amount in the southwest (Taishan Station and its northeast side) of the mountain area is lower (higher) than observations. There are large deviations of precipitation forecast at early morning and afternoon hours. Taking Taishan Station as an example, RMAPS-ST underestimates the rainfall frequency in early morning, which may be related to the forecast deviation of the model on the development and evolution of precipitation system and missed forecasts of weak rainfall events at Taishan Station in the early morning. The intensity of early morning rainfall at Taishan Station is different between forecasts initialized at different times. In the forecast results starting at 20:00 BT, the intensity of early morning rainfall at Taishan Station is significantly overestimated, which leads to the fact that its amount of precipitation is larger than observations. However, the overestimation of precipitation intensity is not obvious in the forecast results starting at 08:00 BT. RMAPS-ST overestimates the frequency of afternoon rainfall at Taishan Station in the results starting at 08:00 BT, which is related to more predicted rainfall events with short duration in the afternoon. The deviation of thermal field and water vapor field is the possible reason for the false precipitation forecast in the afternoon. The characteristics of hourly precipitation have been applied to the operational evaluation system of the regional numerical forecast model of China Meteorological Administration. The results of this paper also indicate that this kind of evaluation is helpful to better understand the forecast ability of the kilometer scale numerical forecasting models for the forecast of diurnal variation of precipitation, and thus provides a more solid scientific basis for the application of precipitation products.

     

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