Statistical characteristics of Dabie-vortex-associated tornadogenesis during an 18-year period (2006–2023)

Abstract

The Dabie vortex (DBV), a mesoscale system frequently generating severe weather in the Yangtze River Basin, exhibits spatial overlap with tornado-prone regions, yet its tornadic potential remains unexplored. This study identifies 23 tornadoes associated with DBV occurring between 2006 and 2023, primarily concentrated in the provinces of Jiangsu, Anhui, Hubei, and Henan. In northern Anhui, DBVs contribute up to 40% of tornadoes—surpassing Jiangsu (~29%) and rivaling half the frequency of tropical cyclone (TC)-induced events. Approximately 70% of tornadoes occur in the DBV's southeastern quadrant, favored by enhanced CAPE, low-level moisture, vertical wind shear, and storm-relative helicity. Most (87%) form during DBV development/maintenance phases, when dynamical forcing peaks. Compared to TC tornadoes, DBV tornadoes exhibit stronger instability and vertical wind shear. Relative to other-type tornadoes, they develop in environments with weaker instability but greater moisture, stronger shear, and greater storm-relative helicity. These findings underscore DBVs as a previously overlooked but critical driver of tornado activity in eastern China.