Colin P. Murray, Steven L. Morey and James. J. O'Brien, COAPS
The role of the mechanisms governing interannual variability of the circulation in the Gulf of Alaska are examined with the Navy Layered Ocean Model 1/16 degree Pacific Ocean simulation (Figure 1). The circulation equation is formed from the model equations and evaluated to quantify the effects of surface wind stress forcing, vorticity advection to the south and west, and dissipation on the vorticity budget of the region. It is found that eddies are formed from the destabilization of the Alaska Current by baroclinic instability concurrent with the arrival of downwelling Kelvin waves generated typically during El Nino years on the equator (Figures 2 and 3). The large anticyclonic eddies can propagate southwestward out of the region resulting in a positive vorticity advection to the Gulf of Alaska. This can serve to balance the fluctuations in the vorticity input by the wind stress over the region.
