【摘要】 利用NCEP6小时一次1°×1°再分析资料、常规高空地面资料和自动站、FY-2C卫星云图及石家庄CINRAD/SA型多普勒雷达等资料,从天气形势、物理机制、雷达回波和云图演变特征、地形作用等方面入手,分析了河北平原一次春季强对流天气的演变和成因。结果表明:这次强对流天气过程发生在高空槽由垂直结构向前倾结构转变的过程中,中高层干冷平流、低层暖湿平流的大气层结增强了对流不稳定的发展,飑线是此次强对流天气的直接影响系统;太行山地形和平原南部的中尺度辐合线,对飑线系统的触发、组织、移动具有重要作用,强对流区发生在地面中尺度辐合线南侧的偏南气流里。分析还发现,低层θse高能区、水汽通量大值区、强的辐合上升区和CAPE的高值区等物理量场都与强对流天气区有较好的对应关系。更多还原

【Abstract】 A severe convection event in the plain of Hebei on May 10,2005 is investigated from such aspects as synoptic situation,physical mechanism,radar echo and satellite image evolution,and the Taihang Mountain forcing,etc.by using the NCEP reanalysis data,conventional observations and the data from automatic weather stations,Doppler radar,Fengyun-2C satellite images.The result shows that the severe convection weather arise in the transition from verticality to forward slant of the upper trough,so there was a different advection between the mid-(cold and dry) and lower-(warm and wet) troposphere,which was quite important to the formation and development of convective instability.The event was triggered by the surface low and meso-scale convergence line,and the squall line was direct influencing system..It is also found that the severe convection area had a better corresponding relation to the high potential pseudo-equivalent temperature(θse) at lower level,large water vapor flux,strong convergence and upward current,and high convective available potential energy(CAPE) during this event.更多还原