摘要：Context.Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles.Aims.We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes.Methods.A first-order perturbation theory approach is used to obtain an expression for the expected shift in the mode frequencies due to perturbations in the internal rotation rate.Results.Using the time-varying rotation from helioseismic inversions we predict the changes in Rossby mode frequencies with azimuthal orders fromm = 1 tom = 15 over the last two solar cycles. The peak-to-peak frequency change is less than 1 nHz for them = 1 mode, grows withm, and reaches 25 nHz form = 15.Conclusions.Given the observational uncertainties on mode frequencies due to the finite mode lifetimes, we find that the predicted frequency shifts are near the limit of detectability.
