Comparison of selected inertial modes computed in the setups that include or exclude the RZ. (a) Velocity eigenfunctions in meridional cross-sections from the CZ-only model. The real part of the eigenfunction corresponds to a longitude ϕ₀ (where u_θ is maximum), while the imaginary part corresponds to the longitude ϕ₀ − π/2m. The m = 1 high-latitude mode is normalized to have the maximum surface velocity of 10 m s⁻¹, while the other modes are normalized to have a maximum surface velocity of 1 m s⁻¹. Solid black curves denote the critical layers of the mode where ℜ[ω]=m(Ω − Ω₀). The frequencies are measured in the Carrington frame. (b) Same as panel a but from the extended model that includes the RZ. Dotted black lines denote the base of the CZ. (c) Horizontal velocity eigenfunctions as functions of latitude at the surface. Dashed blue and solid red curves represent the results with and without the RZ, respectively. The correlation coefficient between the eigenfunctions, 𝒞, defined in Eq. (13), is noted above each subplot. (d) Radial profiles of the RMS velocity.