鹰潭一次局地对流性大暴雨过程的成因分析

Cause analysis of a local convective heavy rain process in Yingtan

为了做好大暴雨的预报预警工作,文章使用FNL 1°×1°,MICAPS、加密自动气象站、雷达回波等多种观测资料,对2020-07-02鹰潭局地大暴雨过程进行分析。结果表明:1)气象925 hPa的高比湿区和地面辐合线极有利于鹰潭出现对流性暴雨;良好的水汽输送和聚集,高低空急流耦合作用形成的深厚上升运动,低层强烈的对流不稳定,为鹰潭出现对流性大暴雨提供了良好的水汽、动力和热力条件。2)强降水位置与地面冷出流的位置对应较好,强降水主要出现在冷出流与环境风形成的地面辐合线及地面暖区的前侧。3)大暴雨主要受多块强回波系统持续影响,回波在鹰潭都有明显的发展加强,主要是由于冷出流形成的偏北气流、环境西南气流以及东部走廊形成的偏东盛行风向在鹰潭持续维持。上述结果为鹰潭大暴雨的预报预警服务提供了分析依据。

In order to do a good job in the forecast and early warning of heavy rain,this paper uses FNL1°×1°,MICAPS,encrypted automatic weather station,radar echo and other observation data to analyze the local heavy rain process in Yingtan on July 2,2020.The results show that:1) the high specific humidity area of 925 hPa and the surface convergence line are very conducive to the occurrence of convective rainstorm in Yingtan.The good water vapor transport and accumulation,the deep upward movement formed by the coupling of the high and low level jets,and the strong convective instability at the low level provide good water vapor,dynamic and thermal conditions for the convective heavy rain in Yingtan.2) The location of heavy precipitation corresponds well with the location of surface cold outflow.The heavy precipitation mainly occurs in the front of the surface convergence line formed by cold outflow and ambient wind and the surface warm zone.3)The heavy rainstorm is mainly affected by the continuous influence of multiple strong echo systems.The echo has obvious development and strengthening in Yingtan,which is mainly due to the northerly airflow formed by the cold outflow,the southwesterly airflow and the easterly prevailing wind direction caused by the eastern corridor.The above results provide an analysis basis for the forecast and early warning service of Yingtan heavy rain.