2014年初春江苏一次高架雷暴成因分析  

The Causes of an Elevated Thunderstorm on 19 March 2014 in Jiangsu

作　　者：曹舒娅 韦芬芬[1] 孙伟 沈建[1] CAO Shuya;WEI Fenfen;SUN Wei;SHEN Jian(Suzhou Meteorological Bereau,Suzhou 215000,China)Abstract)

机构地区：[1]苏州市气象局

出　　处：《沙漠与绿洲气象》2019年第4期88-95,共8页Desert and Oasis Meteorology

基　　金：江苏省气象局科研项目“苏南地区湿对流过程不稳定机制的研究”(JSYBY201915)资助

摘　　要：通过使用NCEP1°×1°客观分析资料,分析了2014年3月19日发生在江苏沿江苏南的一次高架雷暴天气过程。结果表明:此次雷暴过程是江苏初春一次典型的“高架雷暴”天气过程,前期500hPa高空槽引导地面冷空气南下,地面先后受两股冷空气影响,地面附近存在较强逆温,暖湿空气在冷垫之上爬升。850hPa存在浅薄的对流不稳定层以及0~3km强烈的垂直风切变,分别提供了弱热力和强动力不稳定条件。此次过程850hPa附近存在强烈的锋生。雷暴发生的水汽主要源自孟加拉湾,沿江苏南上空存在明显的水汽积聚。雷暴发生期间回波强度最大达55dBZ,移速达75km/h,使得沿江一带自西向东产生雷暴。垂直风廓线上可见此次对流天气有较强的西南暖湿气流。强回波质心发展高度在4.5km左右,强回波发展高度主要在0℃层高度之下,-20℃层高度高于江苏春季冰雹发生时的预报指标,以及垂直上升运动强度不强和伸展高度不高是此次过程没有产生冰雹的主要原因;0℃层高度、-20℃层高度以及大气可降水量均低于江苏春季发生短时强降水的最低指标,是此次过程没有产生大范围短时强降水的主要原因。Based on the 1°×1°NCEP objective analysis data, the meteorological causes of elevated thunder storm occurred on March 19th 2014 in Jiangsu were analyzed. The results showed that the convective weather is a typical elevated thunderstorm weather process. High level trough at 500 hPa carried cold air to the South at surface before thunderstorm occured. Jiangsu was affected by two cold air successively, with strong inversion layer existed near the ground. Warm and wet air climbed along the cold cushion. Shallow convective unstable layer near 850 hPa and 0~3 km strong vertical wind shear provided weak thermal instability and strong dynamic instability condition. There were strong frontolysis near 850 hPa. The water vapor source of this process mainly came from the Bay of Bengal which formed a water vapor channel from there to Jiangsu. The maximum echo intensity and movement speed of second rain belt affected Jiangsu reached 55 dBZ and 75 km/h which make thunderstorm along the river from the west to the East. A strong southwest warm wet air flow on vertical wind profile could be seen. The height of strong echo centroid development is about 4.5 km. The height of strong echo is almost below 0 degree height and the -20 degree centigrade height is higher than hail forecast index of Jiangs, vertical upward motion intensity is not strong enough and the ascending height of vertical motion is not high enough,which is the main reason that no hail appeared in this procedure. 0 ℃ hight and -20 ℃ height as well as pw is much lower than the index of short-time strong precipitation occuerd in Spring of Jiangsu is the main reason that no short -time strong precipitation appeared in this procedure.

关 键 词：高架雷暴 冷垫 逆温层 锋生函数 垂直风切变 

分 类 号：P458.12[天文地球—大气科学及气象学]