一次梅雨锋连续大暴雨过程的诊断分析

Diagnostic Analysis of a Heavy Rain Process on Meiyu Front

为了提高对梅雨锋暴雨过程的预报服务能力,利用常规观测资料、MICAPS天气图和FNL再分析等资料,对2020年7月8—10日梅雨锋连续大暴雨天气过程进行了诊断分析。结果表明:1)这是一次高水汽含量、强低空急流配合短波槽、切变线和梅雨锋天气尺度系统引发的连续大暴雨过程;2)利用FNL再分析资料对过程的水汽、动力、热力条件进行了分析,表明25°~29°N在800 h Pa以下水汽含量丰富,湖南中东部和吉安地区有水汽通量大值区,向东北方向输送水汽并产生明显辐合,且伴有持续的上升运动;3)南昌站的探空CAPE值呈现有利强降水的细长结构,且有明显的能量释放和再建过程;4)稳定天气背景、持续的水汽输送和辐合以及不稳定能量的释放和再建是造成此次连续大暴雨过程的关键所在。研究成果为提高梅雨锋暴雨的预报服务能力提供了参考依据。

In order to improve the prediction service ability of Meiyu Front Rainstorm Process,the continuous heavy rainstorm process of Meiyu front from July 8 to 10,2020 is diagnosed and analyzed by using conventional observation data,MICAPS weather map and FNL reanalysis.The results show that:1)this is a high water vapor and strong jet combined with short wave trough Continuous heavy rain process caused by shear line and Meiyu front weather scale system.2)The FNL reanalysis data are used to analyze the water vapor,dynamic and thermal conditions of the process.It shows that the water vapor content of 25°~29°N is rich below 800 h Pa.There are large value areas of water vapor flux in the Middle East of Hunan and Ji’an,which transport water vapor to the northeast and produce obvious convergence,accompanied by continuous upward movement,lifting water vapor and forming heavy rain.3)The sounding CAPE value of Nanchang Station presents a slender structure favorable for heavy precipitation,and has an obvious process of energy release and reconstruction.4)Stable weather background,continuous water vapor transport and convergence,and the release and reconstruction of unstable energy are the key to the continuous rainstorm process.The research results provide a theoretical basis for improving the prediction service ability of Meiyu Front Rainstorm.