【作者】 刘寿东； 唐玉琪； 邵玲玲； 刘红亚；

【机构】 南京信息工程大学应用气象学院； 上海市中心气象台；

【摘要】 利用LAPS同化系统融合多种观测资料,对2010年8月25日发生在上海的一次强对流天气过程进行中尺度分析。结果表明:这次强对流天气是由中、低空中尺度辐合系统直接触发形成的。强对流形成阶段,地面有分散辐合形成并逐渐加强,成为触发中尺度垂直环流的主要机制,垂直结构上出现低层辐合高层辐散的有利配置,风暴中心附近出现明显的上升气流区,中高层相对湿度显著增加;成熟阶段,强对流云体中心附近的对流层底层开始出现下沉气流,上升气流在其拖曳作用下明显倾斜;衰减阶段,下沉气流加强使中尺度环流动力结构和水气供应受到破坏,垂直结构上转为底层辐散高层辐合。因此,与天气尺度分析相比,基于LAPS的中尺度分析能更深刻地揭示中小尺度系统的三维结构和时空演变特征。更多还原

【Abstract】 A process of severe convection occurred in Shanghai on Aug.25,2010 is analyzed by using LAPS analysis field assimilating varies of meteorological data.As the results indicated,it was trigged directly by mesoscale convergence systems at middle and lower layers.The convergence lines of near surface,distributing separately at first,were gradually promoted to combine by the flow field and developed into strong ones in the formation stage,and became the major triggering mechanism of the mesoscale vertical circulation.In the meantime,the vertical structure contributed to mesoscale convection development,convergence at middle layer and divergence at high layer,the prominent updraft zone located near the storm center,and the relative humidity grew significantly at middle and high layers.In the mature stage,the downdraft drag,which occurred at low layer near the storm centre,made the updraft more slantwise.The mesoscale circulation structure and moisture supply were destroyed in the decaying stage,and the vertical structure was contrary to those in the formation stage.The LAPS analysis field has an advantage in spatial and temporal resolution,which is well revealed the spatial structure and development process of meso and small scale systems in the mesoscale analysis.更多还原