中文摘要：

利用2006～2009年日本再分析资料对长江下游地区梅汛期间（5～7月）边界层内中尺度涡旋进行普查,并分类统计分析了边界层内中尺度涡旋与暴雨、低空急流的关系.研究结果表明：每年的5～7月该地区经常在对流层低层或（和）边界层内出现中尺度扰动涡旋,根据中尺度涡旋最初生成的高度不同,可划分为边界层中尺度涡旋、对流层低层中尺度涡旋和对流层低层一边界层中尺度涡旋三类.边界层中尺度涡旋中与暴雨有密切关系的中尺度涡旋称为边界层中尺度扰动涡旋（PMDV）,根据涡旋前或后6小时累积雨量,可以进一步将其分成两类：第一类是暴雨的直接制造者中尺度对流系统（MCS）先于边界层中尺度扰动涡旋发生（MCS-PMDV）;第二类是边界层中尺度涡旋产生后,激发了中尺度对流,造成了暴雨过程（PMDV-MCS）.PMDV-MCS类涡旋暴雨的特点是在对流层低层850hPa是一条切变线,其南侧有一支西南低空急流,边界层925hPa则是一个闭合的涡旋,暴雨区主要落在涡旋的东北面和东南面.

英文摘要：

A procedure designed for sorting mesoscale vortices is used to sort mesoscale vortices over the lower reaches of the Yangtze River during the periods May-July 2006-2009 by using the Japan reanalysis data with high spatial resolution. The results show that mesoscale vortices （disturbances） are often generated in the lower troposphere and planetary boundary layer （PBL）. Thus, the mesoscale vortices in this area during the meiyu period could be divided into three types： PBL mesoscale vortices, lower troposphere mesoscale vortices, and lower troposphere-PBL mesoscale vortices. Some of the PBL mesoscale vortices, called PBL mesoscale disturbance vortices （PMDVs）, are closely related to rainstorms. Within this group, two distinct patterns of precipitation organization have been identified. One is classified as the MCS-PMDV, which means a mesoscale convection system （MCS） formed before the PMDV. The other is the PMDV-MCS, which is a rainstorm caused by a PMDV. The features of PMDV-MCSs could be identified as follows： a shear line and a low-level jet at 850 hPa, a closed vortex at 925 hPa, and a rainstorm center lying southeast and northeast of the vortex.