Vorticity Budget and Formation Mechanisms of a Mesoscale Convective Vortex in a Heavy-Rainstorm Episode

Mesoscale convective vortices (MCVs) often cause rainstorms. To deepen our understanding of MCV formation mechanisms, reanalysis data from the National Centers for Environmental Prediction and Weather Research Forecasting model were used to simulate activity in East China August 2009. The simulations could reproduce associated activities well. vorticity budget mechanisms then analyzed. results show that planetary advection is much smaller than other terms equation. initiates precipitation region below 800 hPa. When initiates, there are vorticity-variation couplets within vortex, moves towards positive direction. In areas, divergence term tilting source. equilibrium response diabatic heating one forming this MCV. latent-heating level relatively low case, MCV-forming also low. Another mechanism horizontal vortex tube caused by upward motion. At initiation, perturbation scale found be larger Rossby deformation radius, thus have a long duration.