【摘要】 利利用常规气象资料和卫星云图、雷达、自动站等非常规资料,对2012年5月12日夜间发生在广西东部地区的局地短历时强降水进行诊断分析,结果表明:(1)这次特大暴雨具有夏季风降水的特征和性质,它是在副高较弱,南海季风爆发前夕季风涌活跃北抬且西南暖低压强盛的背景下,由500hPa短波槽、850hPa中-α尺度低涡及切变线和地面冷锋共同影响造成的。冷锋前部侵入边界层的浅薄冷空气是此次特大暴雨的触发抬升机制。(2)从多普勒雷达回波和卫星云图特征分析,此次特大暴雨是季风涌和锋面云系相互作用而形成的一个长时间滞留该地的MCS和超级单体所造成。(3)在西南季风活跃时局地强降雨发生前不一定要有西南低空急流的建立。更多还原

【Abstract】 Based on the conventional observation,satellite,radar,and automatic station rainfall data,a short-time strong precipitation,which occurred in Guangxi eastern on the night of May 12,2012,is analyzed.The conclusions are as follows:(1) the rainstorm,which have the features of summer monsoon precipitation,caused by short wave trough at 500hPa,meso-α-scale vortex at 850hPa and cold front with this background that the western Pacific subtropical high is weak,the southwest warm low is strong and the monsoon surge is active forward the north before onset of the monsoon.Cold air intruding into the boundary layer is the triggered mechanism.(2) From the picture characteristics of Doppler radar and satellite,the heavy rain caused by the MCS long-term retention and supercell storm which are formed by interaction of monsoon surge and frontal cloud.(3) During the active monsoon period it does not necessarily establish the southwest low-level jet that can result in the strong rainfall.(4) There are more indication the specific humidity than the water-vapor flux divergence before the heavy rains occurred and it can well provide the reference for now casting.更多还原