Normalized power of sectoral Rossby modes with azimuthal orders t = 2 to 16 obtained from inverting B-coefficients at a depth of 0.98 R_⊙. The black-dashed line is the theoretical dispersion relation of Rossby modes (cf. Eq. (2)) for a uniformly rotating medium at a rate of Ω/2π = 453 nHz. Upper and lower panels: results from analyses of 4 and 8 years of SDO/HMI data, respectively, also mentioned in the titles of each panel. Left and right panels: results for Δℓ = 1 and Δℓ = 3 case, respectively.