We study the latitude and depth dependence of solar Rossby waves. We use horizontal flows from local helioseismology (ring-diagram analysis) at different depths in the solar interior. From these we compute maps of the radial vorticity. We confirm the existence of solar Rossby waves in the sectoral (m = l) power spectra at all depths down to 17 Mm below the surface. The depth dependence of the eigenfunctions is consistent with rm, although this is a weak constraint due to the noise level. The latitudinal eigenfunctions are observed to be more narrow than |sin(θ)|m, likely indicating that the modes sense the latitudinal differential rotation. Furthermore, we detect a non-zero imaginary component of the latitudinal eigenfunctions, possibly related to viscous dissipation. These new observations provide additional constraints on the physics of large-scale Rossby waves in the Sun.
American Astronomical Society Meeting Abstracts #234
- Pub Date:
- June 2019