Sensitivity of an idealised subtropical gyre to the eastern boundary conditions

The flow pattern of the North Atlantic Subtropical Gyre (NASG) is simulated using a highly idealised one-layer quasi-geostrophic wind-driven model. Th e novel feature of the model is the specification of the eastern boundary c onditions. This is an upwelling favourable region with a quasi-permanent so uthward flowing coastal jet, which is fed by the eastern branch of the Cana ry Current. The corresponding boundary conditions are non-zero normal flux and constant potential vorticity, the latter being consistent with the gene ration of anticyclonic vorticity by the coastal jet. We examine the sensiti vity of the model to the eastern boundary conditions and compare the result s with recent observations for the region.