Multiple Equilibrium States of the Loop Current in the Gulf of Mexico

Abstract

It is known that western boundary currents, which encounter a gap in their supporting boundary, assume two dominant steady states: a loop current state and a gap leaping state, and that transitions between these states display hysteresis. However, a question of whether the idealized geometries considered to date apply to the Gulf of Mexico Loop Current (LC) remained. Here, the nonlinear potential vorticity advection-diffusions equations are solved, for Gulf of Mexico topography, using Newton's Method. We demonstrate that, in application to the LC in the Gulf of Mexico, the original conclusions do hold and additionally describe peculiarities of the more realistic steady states that have implications for the LC modeling and forecasting.