Flow around a coastal bend: A model of the Santa Barbara Channel eddy

A steady, equatorward wind stress is applied over a two-layer ocean (infinitely deep lower layer) west of an otherwise straight meridional coast with a right-angle bend. Initial (t ≈ 10 days) response consists of an equatorward current (Kelvin wave) that triggers a cyclone around the bend through viscous production and advection of vorticity, a process akin to eddy shedding in flows without rotation. The response at large times is governed by a Kelvin wave forced by the equatorward weakening of the (assumed positive) wind stress curl, which produces a poleward current near the coast. Application to the Santa Barbara Channel cyclone is discussed, and the cyclone-formation process is further demonstrated with a three-dimensional model with topography and stratification.