Analysis of island-induced wakes with submesocale numerical model outputs around the Korea Strait

Abstract

We investigated the spatial structure and temporal variability of submesoscale eddies [O(1-10)km diameter] persistently generated behind the Tsushima island, based on hourly and 2-km spatial resolution velocity data of the global submesoscale numerical simulation outputs (MITgcm llc4320). As the subsurface currents are correlated with surface currents at the level that we can assume to be barotropic, we analyzed the surface current data to detect where the surface vorticity changes their signs and to identify the spatial and temporal structures of surface circulation statistically associated with island wakes using Empirical Orthogonal Function (EOF). We found that the generation frequency of surface island wakes is in a range of 0.2 to 0.5 cycles per day (2 to 5 days period) and the principal components at the 2nd mode in the EOF analysis show the similar periodicity.