Solitons in a continuously stratified equatorial ocean.

Abstract

The equatorial soliton studies of Boyd are extended to include the effects of continuous vertical stratification. The vertical profiles of density measured in the equatorial Pacific Ocean are used with an idealized profile. The wavenumber intervals of existence/nonexistence of wavepacket solitons are similar to Boyd for the Rossby mode, less similar for the eastward propagating gravity mode, and least similar for the westward gravity mode. Competing resonances and vertical diffusion are discussed. The observed stratification for the equatorial Pacific has a significant effect on solitons. Some of the most dramatic effects are for the KdV solitons of Boyd. It is proposed that the longitudinal variation of stratification may result in the existence of the antisymmetric (with respect to the equator) Rossby solitons in only the western Pacific Ocean. The nonlinear coefficients of the symmetric KdV Rossby soliton decrease monotonically eastward by approximately 30% across the Pacific Ocean. (from authors' abstract)