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.