一次影响靖安的飑线天气过程分析

Analysis of a Squall Line Weather Process Affecting Jing’an

使用地面自动站观测资料、常规气象资料、FY-2G逐小时红外卫星云图、多普勒雷达拼图资料等,采用天气学诊断分析、中尺度分析、形态分析等方法,对2018年3月15日影响靖安的一次飑线天气过程进行分析。结果表明:1)飑线上的强单体回波造成靖安县国家站18:14出现了极大风速18.1 m/s的雷暴大风,18:24-18:50出现了冰雹,冰雹最大直径30 mm,18:00-19:00出现了1h 42.4 mm的短时强降水并伴有强雷电。飑线过境时,伴有由2个≥10 mm/10min超短时强降水组成,风向突变,风速加大并出现雷暴大风,气压上升,相对湿度上升,气温迟后几分钟快速下降。2)500 hPa阶梯槽向东发展移动,呈前顷结构,利于热力和动力不稳定增长;较强的西南暖湿气流,低层湿舌向东北伸展,NE-SW走向的地面辐合线有利于飑线生成、维持和发展。逆温层积累了大量不稳定能量,零度层高度3409 m,-20℃层高度6615m,非常有利于冰雹的生成。3)飑线单体排列趋向紧密,回波强度达到60~65 dBz,中部向南弯曲,弯曲段回波单体强度达70 dBz。飑线回波带的特征主要有两点:一是由多个单体回波紧密排列成带状的回波带或短带形式;二是回波带上强回波单体或超级单体结构。

A squall line weather process affecting Jing'an on March 15,2018 was analyzed by using automatic ground station observation data,conventional meteorological data,FY-2G hourly infrared satellite cloud images,Doppler Radar Mosaic data and other methods,such as synoptic diagnostic analysis,mesoscale analysis and morphological analysis.The results show that:1)squall line weather process affecting Jing'an on March 15,2018.Strong monomer echoes on the line caused thunderstorms and gales with maximum wind speed of 18.1 m/s at 18:14 and hail at 18:24-18:50.The maximum diameter of hail was 30 mm.Short-term heavy rainfall with strong thunder and lightning occurred at 18:00-19:00 hours.When the squall line crosses,it is accompanied by two ultra-short-term heavy precipitation(>10 mm/10min).The wind direction changes abruptly,the wind speed increases and thunderstorms occur,the pressure rises,the relative humidity rises,and the temperature drops rapidly several minutes later.2)500 hPa stepped trough moves eastward,showing a front hectare structure,which is conducive to the unstable growth of heat and power.The strong warm and wet air flow in southwest China extends to the northeast with the low-level wet tongue.It is conducive to thunderstorms,gales and local hailstorms.The ground convergence line along NE-SW direction is beneficial to the generation,maintenance and development of squall line.There is an inversion layer near 925 hPa,which is conducive to energy accumulation.The height of zero layer is about 3409 meters,and that of-20 layer is about 6615 meters,which is conducive to the formation of hail.3)The convective cloud system in southeastern Hubei developed into mesoscale convective system MCS,which moved into northwest Jiangxi and flourished near Jing'an station,resulting in thunderstorms,hail and short-term heavy rainfall in Jing'an.Squall line forms a short echo band consisting of several massive echoes.The short-band monomers are arranged unevenly,and the echo intensity ranges from 55~60 dBz.Short-band echo further develops squall line echo band,monomer arrangement tends to be close,and echo intensity reaches 60~65 dBz.The middle part bends southward,and the strength of the echo monomer in the bending section reaches 70 dBz.There are two main characteristics of squall line echo bands:one is that the echo bands are closely arranged by multiple monomer echoes in the form of bands or short bands;the other is that the echo bands are strong monomer or supermonomer structures.