Eigenfunctions of the equatorial Rossby modes with no radial nodes (n = 0). (a) Real (upper) and imaginary (lower) eigenfunctions of three components of velocity shown in a meridional plane for m = 5. The eigenfunctions are normalized such that the maximum latitudinal velocity is 2 m s⁻¹ at the surface. The solid black line indicates the location of the critical latitudes where the phase speed of a Rossby mode matches to the differential rotation sped. (b) Horizontal eigenfunctions of latitudinal velocity v_θ (upper) and radial vorticity ζ_r (lower) at the surface r = 0.985 R_⊙ for m = 5. The horizontal black dashed lines indicate the location of the critical latitudes at the surface. (c) and (d) are the counterparts of the panels a and b for m = 12.