贵州铜仁一次暴雨天气过程成因分析

2021年6月27日夜间至28日白天,贵州省铜仁市出现一次大范围暴雨天气过程,利用Micaps实况、NCPE再分析及自动站观测资料,对该次暴雨过程的成因进行分析,为日后此类暴雨的预报提供参考。结果表明,该次暴雨过程是副东退至西太平洋上空,高空横槽转竖同时东移南压影响铜仁,配合低层切变线和地面热低压共同影响,造成的强降水天气,暴雨主要出现在高空槽前,低层切变线和地面辐合线附近,位于低空西南急流的北侧;物理量场上,铜仁市位于水汽通量大值区北侧,上空有水汽辐合,为暴雨的形成提供充足的水汽条件,湿层深厚,可转换的对流位能充足,上层大气始终处于对流不稳定状态,暴雨形成的能量条件充沛,垂直速度上升区持续影响铜仁,为暴雨的产生提供动力抬升条件。

A large-scale rainstorm weather process occurred in Tongren City,Guizhou Province from the night of June 27 to June 28,2021.The causes of this rainstorm process were analyzed by using Micaps,NCPE reanalysis and automatic station observation data,so as to provide reference for the forecast of this kind of rainstorm in the future.The results show that the rainstorm process is a sub-east retreat to the western Pacific Ocean,and the upper horizontal trough turns vertical and moves southward to affect Tongren.Based on the joint influence of the low-level shear line and the surface thermal low pressure,the rainstorm mainly occurs in front of the upper trough,near the low-level shear line and the ground convergence line,and is located on the north side of the low-level southwest jet.In the physical quantity field,Tongren City is located on the north side of the high value area of water vapor flux,and there is water vapor convergence above,which provides sufficient water vapor conditions for the formation of rainstorm,the wet layer is deep,the convertible convective potential energy is sufficient,and the upper atmosphere is always in a state of convective instability.The energy conditions for the formation of torrential rain are abundant,and the vertical velocity rising area continues to affect Tongren,providing dynamic uplift conditions for the generation of rainstorm.