热带气旋“弗雷迪”特征及强降水成因初步分析  

Characteristics of Tropical Cyclone“Freddy”and the Causes of Heavy Rainfall

作　　者：杨舒楠 孟庆涛 王皘 姚燕[3] 田林 YANG Shunan;MENG Qingtao;WANG Qian;YAO Yan;TIAN Lin(National Meteorological Centre,Beijing 100081,China;CMA-HHU Joint Laboratory for Hydrometeorological Studies,Beijing 100081,China;National Meteorological Information Center,Beijing 100081,China;National Satellite Meteorological Center,Beijing 100081,China)

机构地区：[1]国家气象中心,北京100081 [2]中国气象局水文气象重点开放实验室,北京100081 [3]国家气象信息中心,北京100081 [4]国家卫星气象中心,北京100081

出　　处：《沙漠与绿洲气象》2025年第1期68-76,共9页Desert and Oasis Meteorology

基　　金：国家重点研发计划揭榜挂帅项目(2022YFC3090602);亚洲合作资金项目:澜湄流域灾害性天气监测预报及其对洪旱、生态农业影响技术应用。

摘　　要：利用全球站点、格点监测,FY-2H卫星等多源观测资料及ERA5再分析资料,对热带气旋“弗雷迪”的生命史和降水特征及莫桑比克南部强降水成因进行分析。结果表明:“弗雷迪”生命史长达36d,为全球寿命最长、南半球跨经度最广的热带气旋。其先后3次登陆,给非洲东南部带来持续强降水和严重洪灾,尤其是莫桑比克南部,降水持续时间长、落区集中、累积量大。“弗雷迪”登陆莫桑比克后处于鞍形场中,引导气流减弱,叠加高空辐散和低层暖湿气流持续输送,大尺度环流为其缓慢移动和维持提供了有利的背景条件。对流层低层辐合和涡度带的发展、强而持续的水汽输送造成莫桑比克强降水的持续。冷空气入侵使莫桑比克南部形成假相当位温梯度大值带;同时中层冷空气增强了大气不稳定性,有利于对流发展。莫桑比克南部受多个中尺度对流系统的连续影响,在提高降水效率的同时也延长了降水持续时间。Using multi-source global station and grid monitoring data,FY-2H satellite data,and ERA5 reanalysis data,this study analyzes the lifecycle and precipitation characteristics of tropical cyclone"Freddy",as well as the causes of heavy rainfall in southern Mozambique.The results show that"Freddy"had a lifespan of 36 days,making it the longest-lived tropical cyclone in the world and the tropical cyclone with the widest latitude span in the Southern Hemisphere.The cyclone made three landfalls,bringing sustained heavy rainfall and severe flooding to countries in Southeastern Africa.In particular,the southern part of Mozambique experienced rainfall with characteristics such as long duration,concentrated areas,and large accumulated amounts.After making landfall in Mozambique,"Freddy"was located in a saddle region,which led to weakened steering winds.Combined with upper-level divergence and the sustained transport of warm,moist airflow by a low-level jet,the large-scale circulation systems provided favorable conditions for the cyclone's slow movement and persistence.The development of convergence and vorticity bands in the lower troposphere,along with strong and sustained water vapor transport,contributed to the prolonged heavy rainfall in Mozambique.Additionally,the intrusion of cold air induced the formation of a high-gradient zone of pseudo-equivalent potential temperature in southern Mozambique.The cold air in the middle layer enhanced atmospheric instability,which facilitated the development of convection.The southern part of Mozambique was continuously affected by multiple mesoscale convective systems,which not only increased precipitation efficiency but also prolonged the duration of the rainfall.

关 键 词：“弗雷迪” 莫桑比克 强降水 冷空气 MCS 

分 类 号：P1458.3[天文地球—天体物理] P444[天文地球—天文学]