摘要
利用常规观测资料、地面自动站资料、多普勒天气雷达资料和FY-2D、FY-2E卫星云图资料等,对江苏2010年8月18日和23日两次发生在副热带高压脊线附近强对流天气进行对比分析。结果表明:(1)在副热带高压控制下,当有足够强的抬升机制时,500 h Pa副热带高压脊线附近也会触发强对流天气,强对流天气发生在925 h Pa切变线和地面辐合线附近。(2)两次强对流天气发生前大气层结不稳定,呈上干下湿状态分布;这两个个例显示雷暴大风强对应于中高层大气干,而短时强降水强对应于低层湿层厚。(3)18日近地层强动力抬升作用,触发了对流风暴;23日抬升凝结高度、自由对流高度及对流温度较低,且没有对流抑制能量,边界层动力抬升和地面热力抬升共同作用触发了对流风暴。(4)多普勒天气雷达径向速度图上出现低空辐合,早于对流风暴新生时间,且低空辐合随时间持续或增强,有利于局地对流风暴的新生和发展,这对临近预报预警有一定的参考意义。
Using conventional observation data, automatic weather station(AWS) data, Doppler weather radar data and FY-2 D & FY-2 E satellite cloud images, comparative analysis is conducted for two severe convective weather events near the subtropical high ridge in Jiangsu on 18 and 23 August 2010. The results indicate that(1) when there is sufficiently strong lifting mechanism, severe convective weather will be triggered in the vicinity of the 500 h Pa subtropical high ridge line, and it is situated near the surface convergence line and 925 h Pa shear line.(2) Atmospheric stratification is unstable before two severe convections are triggered, the lower levels are wet and the upper levels are dry.These two events indicate that the thunderstorm wind corresponds to a dry atmosphere in the middle and upper levels. The short-time heavy rainfall corresponds to thick wet layers in the lower atmosphere.(3) The convective storm is triggered by the surface strong dynamic lifting on18 August. On 23 August, the level of free convection and convective condensation level are low, convection temperature also is low, and there is no convective inhibitory energy. Finally, the boundary layer dynamic lifting and the ground thermal lifting are combined together to trigger the convective storm.(4) The time of the appearance of low-altitude convergence in the radar radial velocity map of Doppler weather radar is earlier than the convective cell generation. The low-altitude convergence is gradually sustained or enhanced with time, which is in favor of the rebirth and development of local convections, which has reference significance for forecasting and warning.
出处
《暴雨灾害》
2017年第5期422-430,共9页
Torrential Rain and Disasters
基金
南通市应用基础研究-社会民生创新计划-民生与社会事业项目(MS12015038)
江苏省气象局预报员专项基金项目(JSYBY201608)
关键词
副热带高压
强对流
地面辐合线
雷达径向速度
抬升机制
subtropical high
severe convection
surface convergence line
radar radial velocity
lifting mechanism
作者简介
张树民,主要从事短期天气预报研究.E-mail：496161156@qq.com
