| description abstract | Deep lateral boundary processes (e.g., western boundary currents) are hypothesized as an alternative energy source exciting the equatorial wave guide at long time scales. A linear, continuously stratified model is used to study the equatorial zonal currents generated by a time dependent, short vertical scale deep zonal jet located at the meridional walls and centered at the equator. Examples of solutions with periodic, transient and spectral forcing are presented. For low frequency forcing at the western or eastern boundaries, energy travels from the source along ray paths associated with Kelvin and long Rossby waves, respectively. Linearly damped solutions look similar in both cases. Solutions show in general a rich baroclinic structure and a complex time dependence (e.g., periodic solutions can exhibit both upward and downward phase propagation and standing mode oscillations at different depths in the water column), with the vertical structure depending, among other factors, on the vertical scale and frequency composition assumed for the boundary jet. Results suggest the potential importance of deep forcing mechanisms to the existence of long time scale, deep baroclinic currents in the equatorial ocean. Solutions are qualitatively similar to observations of the equatorial deep jets, but any detailed comparison between model results and data is premature, given the lack of observational knowledge about the time scales, strength and spatial distribution of deep energy sources. | |
