ON DEEP WESTERN BOUNDARY CURRENTS

The Stommel and Arons [1960a, b] theory of the deep circulation of the world ocean does not directly address the physics of deep boundary cu rrents. In the present paper a maximally simple steady state physics f or deep western boundary currents is developed and integrated into the Stommel-Arons model. This is accomplished by modifying the assumption s of the latter to include effective horizontal eddy viscous terms eve rywhere in the deep water, including in the interior. The resulting so lution for the meridional velocity in a rectangular ocean on a beta pl ane is mathematically analogous to that of Munk [1950] for the wind-dr iven circulation. In the interior the meridional velocity reduces iden tically to that of Stommel and Arons. Among other benefits, the soluti on eliminates the theoretical difficulties associated with the crossin g of the equator by the deep western boundary current. As an initial t est of the theory's consistency with observation, theoretical plots of pressure and meridional velocity as a function of longitude are quali tatively compared with hydrographic sections and inferred meridional v elocity fields in the eastern and western basins of the abyssal North Atlantic. Also, the theoretical profile for the meridional velocity as a function of longitude is qualitatively compared with observations o f longshore velocity as a function of offshore distance in the deep we stern boundary current of the North Atlantic Deep Water.