Effect of Horizontal Resolution on a Meso-β-Scale Vortex Simulation in an Extreme Rainstorm on 22 May 2020 Over South China: A Contrastive Study Based on Different-Resolution Ensembles

被引：1

作者：

Zhang, Guanshun ^{[1
]}

Zhang, Xubin ^{[1
]}

Yang, Zhaoli ^{[1
]}

机构：

[1] China Meteorol Adm, Guangzhou Inst Trop & Marine Meteorol, Guangdong Prov Key Lab Reg Numer Weather Predict, Guangzhou, Peoples R China

来源：

EARTH AND SPACE SCIENCE | 2024年 / 11卷 / 01期

基金：

中国国家自然科学基金; 国家重点研发计划;

关键词：

extreme rainstorm; ensemble prediction system; horizontal resolution; meso-beta-scale convective vortex; potential vorticity; MESOSCALE CONVECTIVE VORTICES; LOW-LEVEL JETS; PART I; HOURLY PRECIPITATION; HEAVY PRECIPITATION; VERTICAL DIFFUSION; EVOLUTION; RAINFALL; ENVIRONMENT; FORECASTS;

D O I：

10.1029/2023EA002921

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

A transient extreme rainstorm that occurred over Guangzhou city, China, on 22 May 2020, has been investigated based on two ensemble prediction systems (EPSs), one with 9-km (TRAMS9km-EPS) and the other with 3-km (TRAMS3km-EPS) grid spacings, respectively. The results show that the better performance in the rainstorm event of TRAMS3km-EPS than that of TRAMS9km-EPS has been attributed to the reasonable simulation of an eastward propagating meso-beta-scale convective vortex (M beta CV). The composite evolution of the good-performing members for the two EPSs has verified the important role of the M beta CV in modulating the structure of low-level jet (LLJ) to converge toward the Guangzhou city, facilitating the formation of the rainstorm. In comparison to the gravity wave disturbance when LLJ passed through the mountains in TRAMS3km-EPS, the topographic effect induced the moist air to ascend deeply in TRAMS9km-EPS, which directly led to earlier outbreaks of convection and rainstorm processes and affected the structural intensity of the upstream M beta CV. Quantitative PV diagnosis has demonstrated that the dispersedly strong high-PV systems in TRAMS3km-EPS were caused by positive feedback effect between meso-scale convective systems and diabatic heating, and were favorable for the entire cyclonic development of M beta CV. The unsymmetrical PV tendency around the moving M beta CV under the combined effect of diabatic heating and advection process in TRAMS9km-EPS resulted in a rapid propagation of this system. However, the symmetrically developed PV system within the M beta CV in TRAMS3km-EPS allowed the enhanced cyclonic circulation to persistently affect Guangzhou city, inducing extreme rainstorms similar to the observations.

引用

页数：22