利用常规气象观测资料、NCEP 1°×1°格点资料、卫星云图和雷达资料对2013年8月1日河南省中南部地区一次强对流过程的中尺度特征及天气成因进行了分析。结果表明：河南中南部地区此次强对流天气过程是由高空槽、副热带高压外围西南气流、中低层切变线及低空急流共同作用产生的。从四川盆地东移过来的对流云团和江淮地区低层切变线上形成的云团在河南中南部地区合并，发展成新的对流云团，使降水量偏高；雷达回波和径向速度特征较明显，造成此次短时强降水和短时大风的对流单体具有明显的出流边界、回波悬垂、弱回波区及有界弱回波等特征。中尺度演变特征表明，一系列中尺度暴雨雨团发生、发展和合并加强成为中尺度对流复合体，且中尺度对流雨团在 CAPE 密集带和地面辐合线附近区域生成，并有向 CAPE大值区及地面辐合线移动发展的趋势。强降水发生前，高层低能舌叠加在低层高能舌上的能量水平分布的垂直配置，导致大气对流性不稳定层结建立；低层正涡度的发展和水平风的切变导致垂直涡度发展，使垂直涡度增大，上升运动增强；高低空急流的耦合作用产生次级环流，触发了对流不稳定能量的释放，产生了强对流天气。%Based on conventional observational data,NCEP 1°×1 °grid data,satellite data and radar data,mesosa-cale features of a convective weather process on August 1,2013 and its forming reasons in the central and southern areas of He′nan province were analyzed.The results show that this process is caused by combined actions of upper trough,subtropical high peripheral southwest air flow,middle and lower shear line and low level jet.Eastward con-vective cloud clusters along the Sichuan basin combine with another one formed in low-level shear line of Jiang-huai region and both become a new cloud cluster,which lead to rainfall higher than average value.Gust fronts,ech-o hanging,weak echo region (WER)and boundary weak echo region (BWER)are quite clear on the PPI and RHI charts of radar reflectivity factors,and features such as divergence on low tilts,large radial velocity region,in-flow flows,divergence in the upper level and convergence in the low level are also evident in the radial velocity chart.The mesoscale evolution suggests that a series of mesoscale rain storm missions generate,develop,consoli-date,strengthen and become mesoscale convective complexes,and the mesoscale convective rain group is generated near area of CAPE dense bands and ground convergence line,with a trend moving to the large value area of CAPE and ground mobile convergence line.Vertical configuration of energy distribution that high-level low-energy tongue superimposed on lower energy tongue leads to establishment of atmospheric convective instability.The de-velopment of vorticity and horizontal wind shear leads to development of vertical vorticity,making vertical vorticity increased and upward motion enhanced.Low level jet coordinating with upper trough generates a secondary circu-lation whose vertical upward branch makes ascending movement strengthened and triggering convective unstable energy release to generate severe convection,and then forms severe precipitation.
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