This paper uses a theoretical model to demonstrate the existence of a group of equatorially trapped, high-frequency (wave-periods shorter than one week), meso-to-small-scale (wave-lengths shorter than 100 km), baroclinic waves which are embedded in a geostrophic current with only vertical shear. Due to their relatively large vertical and meridional velocities, these high-frequency equatorial waves may play an important role in transporting momentum as well as heat energy in the vertical and transequatorial directions.
Ma, Hong. 1996. "High-frequency baroclinic wave motions in an equatorial ocean current and related temperature fluctuations." Journal of Marine Research 54, (6). https://elischolar.library.yale.edu/journal_of_marine_research/2210