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基于多量级TS评分动态权重的多模式融合降水预报方法

A multi-model blending precipitation prediction method based on the dynamic weight of multi-level TS score

  • 摘要: 定量降水网格预报是预报业务的重点和难点,本文设计了一种综合不同量级降水预报性能的多模式融合算法,基于全球尺度模式预报系统(ECMWF)、中尺度模式预报系统(CMA-MESO、CMA-SH9)的24 h累积降水预报,首先采用最优TS评分法对模式预报进行订正,然后基于多量级TS评分计算动态权重融合系数,最后利用概率预报对弱降水消空,并对2022年11月—2023年10月黑龙江省的融合预报结果进行检验及个例应用。结果表明:(1) 最优TS评分法改善了模式预报小量级降水范围偏大的问题,并减小了定量误差,为后续融合提供更高质量成员。(2) 与ECMWF、CMA-MESO、CMA-SH9三种模式预报相比,融合预报晴雨准确率分别提升了12.71%、9.36%、6.4%,暴雨TS评分分别提升了27.14%、45.6%、79.27%。(3) 两次典型个例分析发现融合算法能弥补模式预报强降水落区偏差,有效调整雨区位置和量级,以及改善降水预报空报问题。

     

    Abstract: Quantitative precipitation grid forecast is the focus and challenge in forecasting services. In this study, a muti-mode blending method was conducted which can fully consider the prediction performance of different orders. Based on the global scale model forecast ECMWF, the mesoscale model forecast CMA-MESO, and the CMA-SH9 forecast 24 h cumulative precipitation forecast. The optimal TS score algorithm was used to revise the numerical model, and then the multi-level dynamic weight was used to fuse the revised forecast products. the probability forecast was used to eliminate the weak precipitation. The blending forecast was verified and case applicated for Heilongjiang Province from November 2022 to October 2023. The results are as follows. (1) The forecast corrected by OTS can effectively improve the small precipitation false alarms, reduced quantitative errors, provide higher quality members. (2) Compared with ECMWF, CMA-MESO and CMA-SH9, the accuracy rate of the blending forecast was improved by 12.71%, 9.36% and 6.4%. And the TS score of the rainstorm was improved by 27.14%, 45.6% and 79.27%. (3) Two typical case analyses found that the blending forecast can improve the deviation of the model in the heavy rainfall area, effectively adjust the location and magnitude of rain areas, effectively improve the problem of precipitation false alarms.

     

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