On the Alaskan Stream

Abstract

The Alaskan Stream boundary current south of the uniformly curving coastline formed by the Alaskan peninsula-Aleutian Island chain is examined analytically via steady, barotropic frictional theory. It is shown that, as a result of the changing zonal orientation of this boundary, there is an alteration in the characteristic vorticity balance in the current as it progresses westward from the Gulf of Alaska. Where the curving coastline becomes approximately zonal, this vorticity distribution is such that, unless the clockwise vorticity generated at the coast by the no-slip condition is balanced by a vorticity source external to the current, instabilities and separation of the Alaskan Stream from the coast will occur.