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集合敏感性方法在强降水中期预报中的应用
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作者 丁从慧 魏雯 +3 位作者 柳春 徐怡 隋新秀 谢丰 《内蒙古气象》 2025年第6期17-23,共7页
安徽省气象台主观预报和数值模式对2020年7月17日安徽省强降水过程的中期预报出现了一定的误差。文章利用实况(安徽省2020年7月17日08时—18日08时降水量资料)和ECMWF(简称EC)20时集合预报资料(500hPa位势高度、海平面气压、比湿),基于... 安徽省气象台主观预报和数值模式对2020年7月17日安徽省强降水过程的中期预报出现了一定的误差。文章利用实况(安徽省2020年7月17日08时—18日08时降水量资料)和ECMWF(简称EC)20时集合预报资料(500hPa位势高度、海平面气压、比湿),基于集合敏感性方法对此过程的中期预报进行分析。结果表明:(1)安徽省江北地区降水过程的特点有降水范围广、持续时间长、强度大以及局地性强,大暴雨预报的落区较实况明显偏北。(2)淮北地区南部和江淮地区北部在200hPa上空均形成明显分流,850hPa有低涡影响,低涡南侧与西太平洋副热带高压(简称副高)之间形成了20m·s^(-1)的西南急流,为此次强降水过程提供了充足的动力和水汽条件。(3)利用集合敏感性方法揭示上游地区(新疆维吾尔自治区、内蒙古自治区、青海省和四川省)天气环流系统和下游地区(安徽省江北地区)强降水量级具有相关性,上游地区是安徽省降水的关键敏感区,500hPa环流调整对降水预报转折有着至关重要的作用,且提前预报量能达3~4d。(4)不同起报时间的海平面气压(MSLP)与降水量呈现正负相关性并具有波动性特征,江淮气旋锋面位置对强降水有重要的影响;低层850hPa比湿对预报强降水落区和提前量有较好的指示意义,集合预报最大值分布对预报降水极值具有重要意义。 展开更多
关键词 EC集合预报 中期预报 集合敏感性方法 500hPa位势高度 海平面气压 850hPa比湿
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Precipitation Retrieval from Himawari-8 Satellite Infrared Data Based on Dictionary Learning Method and Regular Term Constraint 被引量:2
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作者 Wang Gen ding conghui Liu Huilan 《Meteorological and Environmental Research》 CAS 2019年第3期61-65,68,共6页
In this paper,the application of an algorithm for precipitation retrieval based on Himawari-8 (H8) satellite infrared data is studied.Based on GPM precipitation data and H8 Infrared spectrum channel brightness tempera... In this paper,the application of an algorithm for precipitation retrieval based on Himawari-8 (H8) satellite infrared data is studied.Based on GPM precipitation data and H8 Infrared spectrum channel brightness temperature data,corresponding "precipitation field dictionary" and "channel brightness temperature dictionary" are formed.The retrieval of precipitation field based on brightness temperature data is studied through the classification rule of k-nearest neighbor domain (KNN) and regularization constraint.Firstly,the corresponding "dictionary" is constructed according to the training sample database of the matched GPM precipitation data and H8 brightness temperature data.Secondly,according to the fact that precipitation characteristics in small organizations in different storm environments are often repeated,KNN is used to identify the spectral brightness temperature signal of "precipitation" and "non-precipitation" based on "the dictionary".Finally,the precipitation field retrieval is carried out in the precipitation signal "subspace" based on the regular term constraint method.In the process of retrieval,the contribution rate of brightness temperature retrieval of different channels was determined by Bayesian model averaging (BMA) model.The preliminary experimental results based on the "quantitative" evaluation indexes show that the precipitation of H8 retrieval has a good correlation with the GPM truth value,with a small error and similar structure. 展开更多
关键词 Himawari-8(H8) RETRIEVAL of PRECIPITATION k-nearest NEIGHBOR (KNN) REGULAR TERM constraints DICTIONARY method Bayesian model average (BMA)
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