On the generalized eigenvalue problem for the Rossby wave vertical velocity in the presence of mean flow and topography

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Tailleux, Remi (2012)

In a series of papers, Killworth and Blundell have proposed to study the effects of a background mean flow\ud and topography on Rossby wave propagation by means of a generalized eigenvalue problem formulated in\ud terms of the vertical velocity, obtained from a linearization of the primitive equations of motion. However, it\ud has been known for a number of years that this eigenvalue problem contains an error, which Killworth was\ud prevented from correcting himself by his unfortunate passing and whose correction is therefore taken up in\ud this note. Here, the author shows in the context of quasigeostrophic (QG) theory that the error can ulti-\ud mately be traced to the fact that the eigenvalue problem for the vertical velocity is fundamentally a non-\ud linear one (the eigenvalue appears both in the numerator and denominator), unlike that for the pressure.\ud The reason that this nonlinear term is lacking in the Killworth and Blundell theory comes from neglecting\ud the depth dependence of a depth-dependent term. This nonlinear term is shown on idealized examples to\ud alter significantly the Rossby wave dispersion relation in the high-wavenumber regime but is otherwise\ud irrelevant in the long-wave limit, in which case the eigenvalue problems for the vertical velocity and pressure\ud are both linear. In the general dispersive case, however, one should first solve the generalized eigenvalue\ud problem for the pressure vertical structure and, if needed, diagnose the vertical velocity vertical structure\ud from the latter.
  • References (16)
    16 references, page 1 of 2

    Aoki, K., A. Kubokawa, H. Sasaki, and Y. Sasai, 2009: Midlatitude baroclinic Rossby waves in a high-resolution OGCM simulation. J. Phys. Oceanogr., 39, 2264-2279.

    de Verdi e`re, A. C., and R. Tailleux, 2005: The interaction of a baroclinic can flow with long Rossby waves. J. Phys. Oceanogr., 35, 865-879.

    Fu, L.-L., and D. B. Chelton, 2001: Large-scale ocean circulation. Satellite Altimetry and Earth Sciences: A Handbook of Techniques and Applications, L.-L. Fu and A. Cazenave, Eds., International Geophysics Series, Vol. 69, Academic Press, 133-169.

    Gill, A. E., 1982: Atmosphere-Ocean Dynamics. Academic Press, 662 pp.

    Gnevyshev, V., and V. Shrira, 1989: Monochromatic Rossby wave transformation in zonal flow critical layer. Izv. Acad. Sci. USSR, Atmos. Oceanic Phys., 25, 628-635.

    Killworth, P. D., and J. R. Blundell, 2004: The dispersion relation for planetary waves in the presence of mean flow and topography. Part I: Analytical theory and one-dimensional examples. J. Phys. Oceanogr., 34, 2692-2711.

    --, and --, 2005: The dispersion relation for planetary waves in the presence of mean flow and topography. Part II: Twodimensional examples and global results. J. Phys. Oceanogr., 35, 2110-2133.

    --, and --, 2007: Planetary wave response to surface forcing and instability in the presence of mean flow and topography. J. Phys. Oceanogr., 37, 1297-1320.

    --, D. B. Chelton, and R. de Szoeke, 1997: The speed of observed and theoretical long extratropical planetary waves. J. Phys. Oceanogr., 27, 1946-1966.

    Maharaj, A. M., P. Cipollini, N. J. Holbrook, P. D. Killworth, and J. R. Blundell, 2007: An evaluation of the classical and extended Rossby wave theories in explaining spectral estimates of the first few baroclinic modes in the South Pacific Ocean. Ocean Dyn., 57, 173-187, doi:10.1007/s10236-006-0099-5.

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