Analysis of the Physical Mechanism of a Persistent Heavy Rain Event in Shanxi Province in October 2021
The persistent heavy rainstorm that occurred in Shanxi province from October 2th to 7th,2021 was analyzed based on meteorological observation data,NCEP/NCAR 1°×1° reanalysis data,and GDAS data.The findings reveal that the cold air behind the stable Ural low trough and mid-latitude short wave trough moved southward and interacted with the warm moist air outside the subtropical high in southwestern China.Simultaneously,a strong upward movement coupled with high and low-level jets maintained the stability of the low-level shear line and surface convergence line,facilitating continuous transport of low-level water vapor which converged to provide favorable conditions for the occurrence and development of persistent heavy rainfall.The heavy precipitation process can be divided into two stages:convective precipitation and stable precipitation.Although there were significant differences in terms of water vapor source,path,and height between the two stages,water vapor transport from southern Shanxi province dominated as a major contributor throughout both stages.Prior to precipitation onset,symmetric instability was observed in the upper troposphere along with a notable increase in precipitable water content.During the convective precipitation stage,frequent intrusion of dry air established rapid convective instability while cooperation between convergence areas of middle-to-lower tropospheric water vapor and strong updrafts resulted in intense convective weather over Shanxi province.Additionally,local extreme heavy precipitation was further enhanced by blocking effects as well as terrain-induced uplift and contraction.
国家科技期刊平台
NSTL
万方数据
