ON RADIATING WAVES GENERATED FROM BAROTROPIC SHEAR INSTABILITY OF A WESTERN BOUNDARY CURRENT

Results from barotropic stability analyses of strong westerly jets generally tend to conclude that those waves that can extract energy from the shear of the jet are largely trapped by the jet. Therefore, the available shear energy of the flow cannot be transmitted by propagating waves away from the strong zone. We show here that the situation is different if the jet is in the meridional instead of the zonal direction. In this case, unstable waves are generated that are able to propagate energy eastward even in the presence of a realistic dissipation. It is then possible for the shear energy of a western boundary current to be transported large distances into the interior of the ocean.