作　　者： (谌伟）; (岳阳）; (刘佩廷）; (邓红）; (张蒙蒙）;

机构地区： 武汉市气象台,武汉430040

出　　处： 《暴雨灾害》 2017年第4期357-364,共8页

摘　　要： 利用GFS再分析资料、常规及非常规观测资料,对比分析了2012年7月12—13日鄂东北特大暴雨中两个连续发生的MCSs(下面分别称为MCS1和MCS2)天气背景、雷达回波特征和地面中尺度系统演变,归纳了MCSs成熟阶段准静止—后向传播结构模型,结果表明:(1)东北冷涡的发展、西风低槽的缓慢东移及副热带高压的稳定导致南北气流长时间交汇于江淮流域形成梅雨锋切变和夜间低空急流的发展,是两个MCSs形成的有利大尺度背景条件。MCS1发生于中层梅雨锋前倾结构下;MCS2则是发展加强于低层梅雨锋切变上。(2)MCS1比MCS2的"冷池"更深厚,与环境温差更大,对流触发更剧烈,但"冷池"运动方向与MCSs传播方向均一致。(3)两个MCSs都出现了后向传播特征,前者可能与大别山脉对冷池的阻挡有关,后者可能与对流更易在不稳定区触发相关;成熟阶段时,MCSs因后向传播,移动缓慢甚至准静止,降水最强。(4)在回波结构上,MCS1向前传播时新生、成熟、消亡单体沿回波长轴自下风方向上风方排列,MCS1及MCS2后向传播时则反之。 Based on GFS reanalysis,conventional observation,Doppler radars and wind profile’s unconventional observations,the extreme precipitation occurred in northeast Hubei province on July12-13st2012is comprehensively analyzed focusing on the movement and structure of two successive MCSs and its development mechanism.The results show:①The two MCSs were under different dynamic mechanisms.MCS1is mainly caused by the strengthening of local Meiyu front and the outburst of thunderstorm.MCS2is characterized by the strong coupling of the low-level Meiyu front shear strong convergence and the high-level strong divergence.②On surface filed,MCS1showed a stronger thunderstorm outburst,a deeper cold pool which spreading mainly along the direction of MCS1,and a more intense convection trigger.③Structurally,when MCSs propagated forward,newborn,mature,and decaying cells lined along the echo long axis and sequentially arranged from downwind to upwind.When MCSs propagated backward,the opposite is true.In mature stage,the MCSs are backward propagated,moved slowly and were even in quasi-static state.Newborn cells line is much more close to the mature one,conducive to the maintenance of MCSs.In that case,the intensity of precipitation is maximized.

关 键 词： 极端降水 中尺度对流系统 冷池 列车效应 准静止 传播