Development and Maintenance Mechanisms of the Vortex during a Rainstorm Process in Northern Guangxi
Based on the conventional observation,satellite data and ERA5 reanalysis data,the development and maintenance mechanism of the vortex that causing regional rainstorm in northern Guangxi during 24-25 May 2020 is analyzed from the dynamic and thermal perspectives.The results show that the vortex occurs firstly at the boundary of Yunnan,Guizhou,and Guangxi,and gradually intensifies and shifts eastward.Convective clouds and precipitation are predominantly observed in the eastern and southern flanks of the vortex.Diagnosis of the vorticity equation reveals the pivotal influence of the vorticity advection term and horizontal divergence term on the evolution and persistence of the vortex.The vorticity transported by the horizontal wind field contributes to the reduction of local vorticity,while the convergence effect acts to amplify it.By decomposing the primary wind field into geostrophic and ageostrophic wind components,the analysis underscores that the changes in local vorticity are predominantly driven by the ageostrophic wind components.Among these components,the horizontal divergence term of the ageostrophic wind yields the most significant positive impact,followed by the torsional term.These factors collectively serve as the primary drivers behind the development and maintenance of vorticity within the system.Moreover,with regard to thermal effects,the study emphasizes the crucial role of positive feedback from latent heating near the mid-level troposphere during the vortex's evolution and movement,facilitating its continued development and sustenance.
万方数据
维普
