基于频率匹配法的中国降水多模式预报订正研究
投稿时间:2019-01-09  修订日期:2019-03-15  点此下载全文
引用本文:
摘要点击次数: 86
全文下载次数: 55
作者单位E-mail
智协飞 南京信息工程大学 气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室, 江苏 南京 210044 zhi@nuist.edu.cn 
吕游 南京信息工程大学 气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室, 江苏 南京 210044  
基金项目:国家重点研发计划重点专项(2017YFC1502000);国家自然科学基金资助项目(41575104)
中文摘要:基于TIGGE资料中欧洲中期天气预报中心、日本气象厅、美国国家环境预报中心及英国气象局1~7 d日降水量预报以及中国自动站观测资料与CMORPH降水产品融合的逐时降水量网格数据集,利用频率匹配法(Frequency-Matching Method,FMM)对中国降水预报进行客观订正。首先利用卡尔曼滤波方法对降水频率进行调整,并根据不同区域降水强度差异将全国分为7个子区域分别进行频率匹配。结果表明,FMM可以有效减小降水量预报的误差。经过频率匹配法订正后各模式降水预报的平均绝对误差(Mean Absolute Error,MAE)大幅减小,且订正后各量级降水的雨区面积更加接近实际观测值。FMM对小于5 mm和大于15 mm的降水预报技巧改进明显。此外,FMM降低了模式预报的小雨空报率和大雨漏报率,并且明显提高了晴雨预报的准确率。FMM明显消除了大范围小雨空报区域,但是对强降水预报FMM仅能调整降水量大小,强降水落区预报并不能得到明显改善。
中文关键词:多模式降水预报  频率匹配法  偏差订正  卡尔曼滤波
 
Calibration of the multimodel precipitation forecasts in China using the frequency matching method
Abstract:In this study,based on the 1-7 day precipitation forecasts from the ECMWF,JMA,UKMO and NCEP in the TIGGE dataset and the hourly precipitation data merged by China Automatic Weather Station(CAWS) and CMORPH precipitation products as the observation data,the precipitation forecast in China is calibrated by using the frequency matching method(FMM).First,the Kalman filter was used to improve the statistics of the precipitation frequency.China was divided into seven sub-regions for the FMM calibration of the precipitation forecasts in accordance with its different precipitation intensity in various regions.The results show that FMM can significantly reduce the forecast error of precipitation intensity and area.Overall,FMM can improve the forecast skill of precipitation at different thresholds.After calibration,the ETS score of the precipitation forecast is significantly improved,and the false alarm rate of light rain and the missing rate of heavy rain are considerably reduced.In addition,the forecast skill for "rain or no rain" events is significantly improved.In addition,FMM can bring the forecast rainfall area closer to the observed values,particularly reducing the false alarm rate of light rain in a vast area.FMM can only improve the intensity and scope of the precipitation by means of adjusting the amount of rainfall.However,the location and shape of the heavy rainfall area cannot be improved.
keywords:multimodel precipitation forecasts  frequency matching method (FMM)  bias correction  Kalman filter
查看全文  查看/发表评论  下载PDF阅读器