• Anderson, D. L. T., and A. E. Gill, 1975: Spin-up of a stratified ocean, with applications to upwelling. Deep-Sea Res., 22, 583596.

  • Anderson, D. L. T., and P. D. Killworth, 1977: Spin-up of a stratified ocean, with topography. Deep-Sea Res., 24, 709732.

  • Cerovečki, I., and R. A. de Szoeke, 2007: How purely wind-driven long planetary geostrophic waves may be energized in the western part of ocean subtropical gyres. J. Phys. Oceanogr., 37, 6070.

    • Search Google Scholar
    • Export Citation
  • Dewar, W. R., and R. X. Huang, 2001: Adjustment of the ventilated thermocline. J. Phys. Oceanogr., 31, 16761694.

  • Kubokawa, A., and M. Nagakura, 2002: Linear planetary wave dynamics in a 2.5-layer ventilated thermocline model. J. Mar. Res., 60, 367404.

    • Search Google Scholar
    • Export Citation
  • Liu, Z., 1993: Thermocline forced by varying Ekman pumping. Part II: Annual and decadal Ekman pumping. J. Phys. Oceanogr., 23, 25232540.

    • Search Google Scholar
    • Export Citation
  • Liu, Z., 1999a: Forced planetary response in a thermocline gyre. J. Phys. Oceanogr., 29, 10361055.

  • Liu, Z., 1999b: Planetary wave modes in the thermocline: Non-doppler-shift mode, advective mode and Green mode. Quart. J. Roy. Meteor. Soc., 125, 13151339.

    • Search Google Scholar
    • Export Citation
  • Liu, Z., and J. Pedlosky, 1994: Thermocline forced by annual and decadal surface temperature variation. J. Phys. Oceanogr., 24, 587608.

    • Search Google Scholar
    • Export Citation
  • Luyten, J., J. Pedlosky, and H. Stommel, 1983: The ventilated thermocline. J. Phys. Oceanogr., 13, 293309.

  • Pedlosky, J., 1965: A study of the time-dependent ocean circulation. J. Atmos. Sci., 22, 267272.

  • Rhines, P. B., and W. R. Young, 1982: A theory of the wind-driven circulation. I. Mid-ocean gyres. J. Mar. Res., 40 (Suppl.), 559596.

    • Search Google Scholar
    • Export Citation
  • Young, W. R., and P. B. Rhines, 1982: A theory of the wind-driven circulation. II. Gyres with western boundary layers. J. Mar. Res., 40 (Suppl.), 849872.

    • Search Google Scholar
    • Export Citation
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Linear Response of a Ventilated Thermocline to Periodic Wind Forcing

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  • 1 Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
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Abstract

This article presents a solution for the linear response of a 2½-layer ventilated thermocline to large-scale periodic wind forcing, with a fixed outcrop latitude. At the eastern boundary, a Rossby wave whose vertical structure is similar to the first baroclinic mode is generated and propagates westward in the shadow zone. Meanwhile, the wave is unstable and amplified westward in the southern region. In the ventilated zone, in addition to the first-mode Rossby wave generated at the eastern boundary, two waves with second mode–like vertical structures are generated. One wave is generated directly by the wind over the outcrop. This wave has a zero zonal wavenumber and southwestward group velocity, such that the eastern edge of the wave migrates westward as it propagates southward. The other wave is generated by interaction between the westward-propagating, first-mode Rossby wave and the outcrop. The zonal wavenumber is the same as that of the first mode at the outcrop, and the phase of the wave propagates southwestward. The crests and troughs of this wave extend across the ventilated zone from the outcrop to the internal boundary between the shadow zone and the ventilated zone.

Corresponding author address: Dr. Atsushi Kubokawa, Faculty of Environmental Earth Science, Hokkaido University, Kita10 Nishi5, Kita-ku, Sapporo 060-0810, Japan. E-mail: kubok@ees.hokudai.ac.jp

Abstract

This article presents a solution for the linear response of a 2½-layer ventilated thermocline to large-scale periodic wind forcing, with a fixed outcrop latitude. At the eastern boundary, a Rossby wave whose vertical structure is similar to the first baroclinic mode is generated and propagates westward in the shadow zone. Meanwhile, the wave is unstable and amplified westward in the southern region. In the ventilated zone, in addition to the first-mode Rossby wave generated at the eastern boundary, two waves with second mode–like vertical structures are generated. One wave is generated directly by the wind over the outcrop. This wave has a zero zonal wavenumber and southwestward group velocity, such that the eastern edge of the wave migrates westward as it propagates southward. The other wave is generated by interaction between the westward-propagating, first-mode Rossby wave and the outcrop. The zonal wavenumber is the same as that of the first mode at the outcrop, and the phase of the wave propagates southwestward. The crests and troughs of this wave extend across the ventilated zone from the outcrop to the internal boundary between the shadow zone and the ventilated zone.

Corresponding author address: Dr. Atsushi Kubokawa, Faculty of Environmental Earth Science, Hokkaido University, Kita10 Nishi5, Kita-ku, Sapporo 060-0810, Japan. E-mail: kubok@ees.hokudai.ac.jp
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