Relative importance of planetary β effect ($\mathfrak{R}[{\mathcal{G}}_{\mathrm{planetary}}]$), compressional β effect ($\mathfrak{R}[{\mathcal{G}}_{\mathrm{comp}}],\mathfrak{R}[{\mathcal{W}}_{\mathrm{comp}}]$), topographical β effect ($\mathfrak{R}[{\mathcal{W}}_{\mathrm{topographic}}]$) and other terms in the vorticity equation to determine the propagation and frequency of the n = 0 equatorial Rossby mode (m = 3) in the compressible and Boussinesq models, under uniform rotation. Refer to Eqs. (16) - (21) for the definition of the various quantities. A negative quantity implies that the associated physical effect promotes retrograde propagation, while a positive quantity implies that its physical effect promotes prograde propagation. The respective frequencies of the modes are specified on the left. We normalize the eigenfunctions from the different models to have the same integrated kinetic energy density such that the maximum absolute value of ℜ[ω|ζ_r|²] is 100 for the compressible model.