2019年9月12—14日陇南市持续性暴雨天气成因分析

Causes of Continuous Rainstorm in Longnan City During September 12th-14th,2019

本文对2019年9月12—14日陇南市出现的一次持续性暴雨天气过程的成因进行了分析。结果表明:此次强降水天气过程中副热带高压外围有较强的西南气流稳定维持,同时700 hPa存在明显的强风速带的辐合,低层强烈辐合为暴雨的发生、发展提供了动力条件;对物理量场分析发现,这次持续暴雨过程中,中低层有明显的湿层及水汽辐合,为降水提供了充足的水汽条件;对流云团演变特征表明,此次持续性强降水是在青海东南部的对流云与四川北部的对流云系东移合并加强后逐渐减弱的过程中发生的,具有明显的局地性。

This paper analyzed the causes of the continuous rainstorm weather process in Longnan City during September 12th-14th,2019.The results showed that there was a strong southwest airflow that stably maintained in the periphery of the subtropical high during the strong precipitation weather process.At the same time,there was an obvious convergence of strong wind belt at 700 hPa,and the strong convergence in the lower layer provided the dynamic conditions for the occurrence and development of the rainstorm.Through the analysis of the physical quantity field,it was found that there was an obvious convergence of moisture and water vapor in the middle and lower layers during the continuous rainstorm process,which provided sufficient water vapor conditions for precipitation.The evolution characteristics of convective cloud clusters indicated that the continuous heavy precipitation occurred in the process of moving eastward,merging,strengthening and gradually weakening of convective cloud system in southeastern Qinghai and northern Sichuan,which had obvious local characteristics.