Dimensionless dispersion relations of various equatorially trapped tidal waves (eqs. [7] and [10]). The upper solid lines (﹩n=1﹩, 2, 3…) for Poincaré waves (eq. [11]); the lower solid lines (﹩n=1﹩, 2, 3… without labeling ﹩n=2﹩) for Rossby waves (eq. [12]); the dash‐dotted line for mixed Rossby‐Poincaré waves (eq. [14]); and the straight dashed line for Kelvin waves (eq. [7]).