Preconvective environments of severe convective winds over North China and South China

This study aimed to identify the environmental discrepancy between severe convective wind (SCW) and climate background over North China and South China and between SCW occurring in these two regions, which were prone to SCW in China. 17 parameters from 11,727 (13130) climate background soundings and 4404 (2513) SCW soundings in North (South) China were quantitatively investigated. These parameters were grouped as significant important parameters (SIP), moderate important parameters (MIP), and weak important parameters (WIP). The skill in discriminating the environments between SCW and climate background steadily decreased from SIP to MIP and then to WIP. In North China, SCW typically occurred under moderate to severe deep wind shear and low convective available potential energy (CAPE) conditions. However, in South China, SCW tended to occur at low CAPE and moderate deep wind shear, as well as moderate CAPE and moderate to severe deep wind shear. Compared to the background climate, the SCW environment was associated with considerable instability, high shear, and dry and cold air in the middle layer over both North and South China. A substantial variation in wind shear was identified between the SCW and background in North China, whereas a considerable difference in comprehensive conditions involving CAPE and wind shear was detected in South China. The SCW environment is characterized by a steeper lapse rate in the middle layer as well as a higher Total Totals index in North China than in South China, while the opposite was true for CAPE between two regions. In general, the thermal parameter discrimination was larger than the shear metric discrimination when comparing the soundings for the two regions.