【摘要】 对2004年7月16、17日出现在临沂市的大暴雨过程的进行中尺度分析,应用MM5v3.6非静力中尺度模式,用美国NCEP再分析资料作初始场,采用双向三重嵌套模式,进行高分辨的数值模拟。分析揭示了这次大暴雨的天气尺度背景和中尺度系统的发生和发展的结构及演变,结果表明:高低空急流的有利配合为暴雨过程提供环境条件,大暴雨出现在高空西风急流轴线出口区与低空西南风急流轴向出口区北侧之间;数值模拟看出:在强降水产生时,雨区上空存在较强的中-β尺度系统,该系统有强而窄的垂直上升运动、上下垂直的辐散辐合结构,强烈的对流不稳定,在对流层低层还存在对称性不稳定。低空急流提供充沛的水汽,并通过强而窄的上升运动向高层输送。更多还原

【Abstract】 During July 16—17,2004,an abrupt heavy rainstorm occurred in Linyi region in the south- east of Shandong province,this event has successfully simulated by the model MM5.V3.6.Giving the ini- tialization of re-analysis NCEP data,the MM5 v3.6 model includes non-hydrostatical physics and two-way model with triple nest grid and high spatial resolution.Analyzing the structure and evolution at synoptic scale and meso-βsystems,the main results are as follows:the strong west jet at high level and the strong southwest jet at low-level offer suitable environment conditions,the heavy rainfall appeared at the north- ward of high-level jet and low-level jet axis,where the jet at high level and the jet at low level intersect. During the heavy rainstorm process,there are strong meso-βvortex systems over rainfall area,it is charac- terized by a strong and narrow vertical ascent stream,the convergence at low level and the divergence at high level vertically,abundant water vapor transmitted,and heavy convection non-stabilization,even a con- ditional symmetric instability at low level.更多还原