Diagnosing the role of eddies in driving the circulation of the northwest Atlantic Ocean

In this letter we present a variation of the recently proposed “semi-prognostic method” for use with ocean models. The new version has the advantage that model drift is effectively prevented, while at the same time the meso-scale eddy field is free to evolve. We use the method to probe the importance of the eddy-driven circulation in the northwest Atlantic Ocean. For the particular model we use here, it is shown that the eddies strongly reinforce the eastward Gulf Stream jet and the northern recirculation in the slope region, with over 50% of the total transport of this recirculation being directly eddy-driven. The eddies also play a role in setting the temperature and salinity properties of the “northwest corner” southeast of Newfoundland.