Oceanic motions are partly driven by thermal forces associated with differential heating of the surface waters between tropical and polar regions. In this study thermal driving is parameterized in a two-layer system by an assumed upwelling of fluid through the interface. The upwelling is steady and horizontally uniform wherever upper-layer water is present. With an assumed constant depth of the interface along the eastern boundary the transports of the upper and lower layers and the interface distribution are derived for the interior ocean....