On the modelling of equatorial waves

The present theory of geophysical waves that either raise or lower the equatorial thermocline, based on the reduced‐gravity shallow‐water equations on the β ‐plane, ignores vertical variations of the flow. In particular, the vertical structure of the Equatorial Undercurrent is absent. As a remedy we propose a simple approach by modeling this geophysical process as a wave‐current interaction in the f ‐plane approximation, the underlying current being of positive constant vorticity. The explicit dispersion relation allows us to conclude that, despite its simplicity, the proposed model captures to a reasonable extent essential features of equatorial waves.