热带气旋西行造成的远距离降雨特征分析

2018年7月27~28日凉山州地区出现了持续性的强降水天气过程,本文运用水平分辨率为1°×1°的NECP6小时再分析资料、新型监测资料及常规观测资料进行分析。发现此次过程不同于常规的降水过程,环流背景上受副高外围的东南气流和热带气旋形成的东风波倒槽共同作用形成的急流轴影响,为降水地提供充足的水汽和能量补充,从而形势上形成了热带气旋远距离降水,同时副热带高压的稳定维持也阻挡了高原上的低值系统快速东移,使得降水机制长时间停滞,对降水地造成影响。

Characteristics of Long Distance Rainfall Caused by Westward Movement of Tropical Cyclones

Continuous heavy rainfall occurred in Liangshan from July 27 to 28,2018.In this paper,the NECP 6-hour reanalysis data,new monitoring data and conventional observation data with horizontal resolution of 1° × 1° are used for analysis.It is found that this process is different from the conventional precipitation process.The circulation background is influenced by the jet axis formed by the southeast airflow around the subtropical high and the easterly wind wave inverted trough formed by the tropical cyclone,which provides sufficient water vapor and energy for the precipitation area,thus forming the long-distance precipitation of the tropical cyclone and the subtropical high.Pressure stability also prevents the low-value system from moving eastward rapidly,which makes the precipitation mechanism stagnate for a long time and affects the precipitation land.