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CMA-MESO与ZJ3KM模式对浙江省短时强降水预报能力的精细化对比分析

Refined performance comparison between CMA-MESO and ZJ3KM in forecasting short-term heavy precipitation over Zhejiang Province

  • 摘要: 为深入评估中国气象局区域中尺度数值预报系统(China Meteorological Administration Mesoscale Model,CMA-MESO)与浙江快速更新同化预报系统(Zhejiang WRF-ADAS Rapid Refresh System,ZJ3KM)对浙江省短时强降水的精细化预报能力,本文基于2023年6—9月五类典型天气背景(冷切型、暖切型、高空槽型、热带气旋型、副高控制型)的短时强降水,综合运用过程检验、传统检验、邻域检验FSS (Fractions Skill Score)评分及MODE (Method for Object-Based Diagnostic Evaluation)检验,从降水强度落区预报、小时尺度特征、空间结构等多方面系统评估两模式的预报性能。 结果表明:(1) 空间分布上,CMA-MESO对暖切型和热带气旋型降水的落区与频率预报效果更优,ZJ3KM在冷切型和副高控制型的降水总量、频率及强度空间分布上更具优势,两模式对高空槽型的预报均存在显著偏差。(2) 日变化特征方面,CMA-MESO整体接近实况但低估副高控制型降水,ZJ3KM普遍高估降水频率且峰值时间偏早。(3) 传统检验显示,CMA-MESO在热带气旋型的TS评分更高、空报率更低,ZJ3KM在副高控制型表现更优且多数类型下命中率更高、范围偏差更小。(4) 空间检验表明,CMA-MESO在热带气旋型占优,ZJ3KM在其余类型降水强度指示性更好但落区存在偏差。两模式均存在强降水对象识别不足的问题,CMA-MESO在冷、暖切型的空间匹配度更好,ZJ3KM在其他三类中表现更优;位置偏差方面,除冷切型外CMA-MESO多偏东偏南,ZJ3KM多偏东偏北。基于此,使用时可考虑对CMA-MESO的趋势演变信息和ZJ3KM的强度及局地小尺度信息进行综合研判,结合两模式的位置偏差做好针对性订正。

     

    Abstract: To better understand the forecasting performance of the China Meteorological Administration Mesoscale Model (CMA-MESO) and the Zhejiang WRF-ADAS Rapid Refresh System (ZJ3KM) for short-term heavy precipitation in Zhejiang Province, this study systematically assesses the two models using precipitation process verification, traditional verification methods, as well as FSS (Fractions Skill Score) and MODE (Method for Object-Based Diagnostic Evaluation). The analysis is based on short-term heavy precipitation events associated with five typical synoptic patterns—cold shear, warm shear, upper-level trough, tropical cyclone, and subtropical high—during June–September 2023. Model performance is assessed in terms of rainfall intensity, spatial distribution, diurnal cycle, and structural characteristics.The results indicate: (1) CMA-MESO performs better in capturing the rainfall coverage and frequency for warm-shear and tropical cyclone types, whereas ZJ3KM exhibits superior skill in simulating the total precipitation, frequency, and intensity distributions for cold-shear and subtropical high types. Both models show pronounced biases for upper-level trough cases. (2) Regarding diurnal variation, CMA-MESO generally matches observations but underestimates precipitation in the subtropical high type, whereas ZJ3KM tends to overestimate precipitation frequency and advance the timing of peak rainfall. (3) CMA-MESO achieves a higher Threat Score (TS) and lower false alarm rate for the tropical cyclone type, whereas ZJ3KM performs better for the subtropical high type and achieves higher hit rates and smaller domain biases for most precipitation types. (4) Spatial verification indicates that CMA-MESO performs better for tropical cyclone, while ZJ3KM provides superior precipitation intensity indication for other types, albeit with location biases. Both models show insufficient identification of heavy precipitation objects. Regarding spatial matching, CMA-MESO demonstrates better performance for cold- and warm-shear cases, whereas ZJ3KM excels in the remaining three categories. For position bias, except in cold shear, CMA-MESO tends to have eastward and southward deviations, while ZJ3KM shows eastward and northward biases. Overall, optimal operational application should integrate the strengths of both models--leveraging CMA-MESO's trend evolution information, and ZJ3KM's intensity and local small-scale details, while applying targeted corrections to mitigate their respective location biases.

     

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