On the Revival Mechanism of Typhoon Doksuri (2023) Remnants After Its Landfall

After landfall, tropical cyclone (TC) remnants may maintain or even rejuvenate and incur catastrophic disasters. What leads to the revival of TC remnants over land remain elusive. In this study, the revival mechanism of Typhoon Doksuri (2023) remnants is extensively explored. Doksuri brought severe damage to the Chinese mainland after its landfall. The remnants vortex of Doksuri sustained an inland trajectory for 3 days and underwent a total maintenance of 60 h, among which a revival of 18 h. Based on multi-source observations and ERA5 reanalysis data, by calculation of moist potential vorticity and analysis of slantwise vorticity development (SVD), this study unveils that while maintaining a significant warm-core structure over the course of maintenance and revival, the Doksuri remnants transported sufficient moisture in the mid-lower troposphere, which intensified the north-south temperature and humidity gradients, causing tilting of the isentropic surfaces remarkably. According to the SVD theory, the tilting gave rise to vorticity development and forced upward air motion on the northern side of the remnant vortex. Moreover, numerical sensitivity experiments based on the WRF model reveal that the topography of Taihang Mountains and the diabatic heating associated with surface and convective latent heat fluxes also played important roles in the revival of the Doksuri remnants. The dynamic and thermodynamic mechanisms derived by this study will help improve understanding and predicion of the disasters induced by TC remnants.