The Key Mesoscale Systems and Mesoscale Vortices of the Henan Extreme Precipitation in 2021

Based on the Doppler weather radar and surface observations, key mesoscale systems features of rainstorm structure during period extreme precipitation in Henan province 20 July 2021 are investigated. The results show that a nearly meso-α-scale West Low Vortex (WHLV) near Songshan Mountain, front, horizontal shear convergence line lower troposphere two strong low-level jets (LLJs) were main triggered process. Many vortices including meso-β-γ-scale (i.e., meso-vortices) found within WHLV. Hourly over 50 mm was mostly caused by storms with meso-vortices. In heaviest stage Zhengzhou Storm (ZZS), clear meso-vortex above 2 km AGL identified diameter 15–20 vorticity 1.0–2.0 × 10−3 s−1, while its lifetime about h. ambient airflows converged into storm from north, east south, forming promoted development storm. Strong uplift occurred along edge storm, easterly LLJ shallow outflow strongest updraft under at northeast end when short-lived meso-γ-scale vortex formed area. Both merge convective cells resulted eastward propagation ZZS.