The Xiamen Symposium on Marine Environmental Sciences (XMAS 2027)

The southern coast of Korea is characterized by energetic barotropic tidal flows interacting with complex island–channel topography, leading to the recurrent generation of tide-driven submesoscale eddies (TSMEs). Using a high-resolution depth-averaged barotropic model, we investigate TSMEs generated within Yokji-myeon coastal system, where energetic tidal jets, flow separation, and intense horizontal shear repeatedly organize transient eddies that leave persistent imprints on the residual gyres. The residual vorticity balance is primarily governed by mean vorticity advection and eddy vorticity flux divergence, indicating rapid redistribution of vorticity associated with accelerating and curving tidal jets. Energetic analyses further show that barotropic shear instability provides the principal pathway for TSMEs growth, with persistent mean-to-eddy kinetic energy (KE) conversion concentrated along frontal shear zones surrounding topographically constrained tidal jets. The evolving TSMEs additionally mediate bidirectional KE transfer across spatial scales. Downscale transfer dominates during the growth stage of energetic tidal jets, whereas localized upscale transfer emerges around mature and decaying vortices, indicating partial redistribution of KE back toward the larger-scale tidal flow. Together, these results suggest that TSMEs actively couple oscillatory tidal forcing, residual circulation, and cross-scale energy transfer within strongly tide-dominated coastal systems, with potentially important implications for coastal mixing and material transport.