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基于葵花卫星和人工智能的MCS降水临近预报模型构建及其检验应用

Application of Geostationary Satellite and Artificial Intelligence-Based Precipitation Prediction for the 23.7 Extreme Heavy Precipitation Event in North China

  • 摘要: 为提升高强度降水、暴雨等极端降水事件的预报准确率,满足高分辨率预测需求,使用Himawari-89卫星红外波段亮温数据、中国地面自动站降水数据和ERA5再分析物理量资料,利用卫星云顶亮温资料识别中尺度对流系统(Mesoscale Convective System, MCS),将机器学习特征算法筛选的特征变量作为模型输入数据,运用Stacking集成学习算法建立分类—回归模型,以预测未来1 h降水量,并应用 TS(Threat Score)评分、相关系数等指标对预报结果进行检验分析。并运用该模型对华北“23.7”极端强降水过程小时降水量进行预测验证。结果表明:静止气象卫星云顶亮温数据在降水类型识别,乃至降水定量预测方面都有显著作用;分类—预测算法在中尺度对流系统降水邻近预报方面表现良好,相关系数和均方根误差分别为0.811和0.14 mm/h,预测结果优于单独回归模型;在华北“23.7”极端强降水案例中,小雨TS评分达0.58,对降水空间分布的预测与实况吻合度较高,融合模型具有更强、更稳定的预报性能。

     

    Abstract: To improve the prediction accuracy of extreme precipitation events, such as high-intensity precipitation and rainstorms, and to meet the demand for high-resolution and high-frequency predictions, this study used the Himawari-8 infrared band brightness temperature data, China’s Automatic Weather Station precipitation data, and ERA5 reanalyzed physical quantity data. This study then identified the mesoscale convective system (MCS) by using the cloud top temperature data of the satellite; used the feature variables screened by the machine learning feature algorithm as model input data; established a classification model and regression model with the Stacking integrated learning algorithm to predict the precipitation in the next hour; tested and analyzed the prediction results with indicators such as the Threat Score, confusion matrix, and correlation coefficient. The model was used to predict the hourly precipitation of the 23.7 extreme heavy precipitation event in North China. The results showed that the cloud top temperature data obtained by the stationary meteorological satellite significantly affects the identification of the precipitation type and quantitative prediction of precipitation. Further, the classification-prediction algorithm performed well in rainfall nowcasting for the MCS, with a correlation coefficient and root-mean-squared error of 0.811 and 0.14 mm/h, respectively. These prediction results are better than those obtained by individual regression models. For the 23.7 extreme heavy precipitation in North China, the TS score reached 0.58, and the forecast of the spatial distribution of precipitation agreed well with the actual distribution. In general, the fusion model realized a stronger and more stable prediction performance, and its prediction effect for samples with large precipitation should be further improved.

     

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