2015年5月18-19日江西南部区域性暴雨天气过程成因

摘要

利用常规气象观测资料及NCEP/NCAR 1°×1°再分析资料,对2015年5月18-19日发生在江西南部的区域性大暴雨天气过程的雨情及影响系统进行了分析.结果表明,中高纬度地区东北冷涡东移南调,引导其南侧高空槽东移,并引发弱冷空气南下;副热带高压偏强且维持在18°N附近.弱冷空气与副热带高压北侧西南急流持续交汇有利于江西南部地区出现大暴雨的稳定环流型.副热带高压西北侧旺盛的水汽输送及辐合在江西南部的维持为大暴雨的发生提供了充足的水汽条件.多尺度系统相互作用导致江西南部的东北部局地较强的静止锋锋生作用是此次大暴雨天气过程发生的主要天气学成因.%Based on the conventional meteorological observation data and NCEP/NCAR reanalysis data, the severe rainstorm process happened in southern Jiangxi during 18-19 May 2015 was analyzed in this paper.The results indicated that, the northeast cold vortex in the high latitude moved eastward, leading the south side of the trough moving eastward and the weak cold air to the southern China.The subtropical high was strong and maintained in the vicinity of 18°N.The continuous convergence between weak cold air and the southwest jet on north side of the subtropical high was conducive to the stable circulation of heavy rain in southern Jiangxi.The transportation and convergence of exuberant water vapor on the northwest side of the subtropical high provided adequate moisture for the heavy rain.The interaction of multi-scale systems led to the formation of local strong stationary front, which was the main causes of the heavy rain.