A numerical investigation of effects of a tilt of the zero wind stress curl line on the subduction process

A three-dimensional ocean general circulation model is used to investigate the effects of an idealized, nonzonal wind stress curl on the subduction process in the subtropical gyre. Idealized zonal winds are used to force the model ocean. Analyses of potential vorticity, water particle trajectories, and tracer-injection experiments are conducted. Two characteristic features appear in response to the nonzonal distribution of the wind stress curl: an upwelling region occurs in the subtropical gyre, and a downwelling region extends northward in the northeastern corner of the subtropical gyre. In comparison to results obtained from a zonal wind stress curl, a pool region, where there is no signal from the surface of the subarctic region, shrinks, a ventilated region becomes deeper, and the subducted water has a wider range of potential density.