Abstract:

Based on conventional observation data，automatic meteorological station data and radar data，the mesoscale analysis of a squall line process influenced on Tangshan area on August 4，2013 was performed．The results showed that the 500 hPa upper trough was the main effect system on the squall line induced by a ground mesoscale convergence line．The invasion of dry and cold air from the middle troposphere and the convergence of warm and moist air from the lowlevel troposphere enhanced the instability of atmosphere．The low‐level convergence and high‐level divergence further strengthened the vertical movement．The vertical wind shear at the middle and low layer was beneficial to the development，enhance and maintain of the squall line．Some mesoscale structure features can be identified on the radar echo map，such as mesoscale convergence line in middle and low level，bow echo，head wind areas，which were all actual indicative to the severe convective weather．

Key words:  squall line, mesoscale, instability stratification, radar echo characteristic

摘要：

利用常规观测资料自动气象站资料及雷达资料，对2013年8月4日影响唐山的一次飑线过程进行了中尺度分析。结果表明：500 hPa高空槽是产生这次飑线的主要影响系统，地面中尺度辐合线是这次过程的触发机制；对流层中层干冷空气入侵与低层暖湿气流的辐合增强了大气层结的不稳定；低层辐合高层辐散进一步加强了垂直运动的发展;中低层垂直风切变则有利于飑线的发展加强和维持。雷达回波图上可识别出中低空的中尺度辐合线、弓形回波、逆风区等中小尺度结构特征，对于此类强对流性天气的预报具有实际指示意义。

关键词: 飑线, 中尺度, 不稳定层结, 雷达回波特征