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 investi gate the effects of an idealized, nonzonal wind stress curl on the sub duction process in the subtropical gyre. Idealized zonal winds are use d to force the model ocean. Analyses of potential vorticity, water par ticle trajectories, and tracer-injection experiments are conducted. Tw o characteristic features appear in response to the nonzonal distribut ion of the wind stress curl: an upwelling region occurs in the subtrop ical gyre, and a downwelling region extends northward in the northeast ern 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 regio n becomes deeper, and the subducted water has a wider range of potenti al density.