Diagram of ν vs. based on Rossby modes of Model A with ν_rot = 7 μHz. Each mode corresponds to an open blue circle, and the dashed and solid lines indicate the fitted lines of the first and fifteenth iteration, respectively. The open square at the abscissa intercept represents the converged value of ν_rot. Small open orange circles indicate the corrected values that are calculated for the converged value of ν_rot.