• Chen, P., M. P. Hoerling, and R. M. Dole, 2001: The origin of the subtropical anticyclones. J. Atmos. Sci., in press.

  • Dickinson, R. E., 1980: Orographic Effects in Planetary Flows. GARP Publication Series, No. 23, WMO, 450 pp.

  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc., 106:447462.

  • Held, I. M., 1983: Stationary and quasi-stationary eddies in the extratropical troposphere: Theory. Large-Scale Dynamical Processes in the Atmosphere, B. J. Hoskins and R. P. Pearce, Eds., Academic Press, 127–168.

    • Search Google Scholar
    • Export Citation
  • Holton, J. R., 1992: An Introduction to Dynamic Meteorology. 3d ed. Academic Press, 511 pp.

  • Manabe, S. and T. B. Terpstra, 1974: The effects of mountains on the general circulation of the atmosphere as identified by numerical experiments. J. Atmos. Sci., 31:342.

    • Search Google Scholar
    • Export Citation
  • Marshall, J. and D. W. K. So, 1990: Thermal equilibration of planetary waves. J. Atmos. Sci., 47:963978.

  • Pedlosky, J., 1987: Geophysical Fluid Dynamics. 2d ed. Springer-Verlag, 710 pp.

  • Roads, J. O., 1982: Forced, stationary waves in a linear, stratified, quasi-geostrophic atmosphere. J. Atmos. Sci., 39:24312449.

  • Rodwell, M. J. and B. J. Hoskins, 1996: Monsoons and the dynamics of deserts. Quart. J. Roy. Meteor. Soc., 122:13851404.

  • Smagorinsky, J., 1953: The dynamical influence of large-scale heat sources and sinks on the quasi-stationary mean motions of the atmosphere. Quart. J. Roy. Meteor. Soc., 79:342366.

    • Search Google Scholar
    • Export Citation
  • Webster, P. J., 1972: Response of the tropical atmosphere to local, steady forcing. Mon. Wea. Rev., 100:518541.

  • White, G. H., 1982: An observational study of the Northern Hemisphere extratropical summertime general circulation. J. Atmos. Sci., 39:2440.

    • Search Google Scholar
    • Export Citation
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Thermally Forced Stationary Waves in a Quasigeostrophic System

Ping ChenNOAA–CIRES Climate Diagnostics Center, Boulder, Colorado

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Abstract

Analytical solutions of thermally forced stationary waves in a linear quasigeostrophic model are obtained. It is found that the zonal flow has a profound impact on the structure of the responses. The inviscid solutions on a resting basic state are the Sverdrup solutions that are confined to the heating region. The solutions on a westerly zonal flow are composed of a local and a vertically propagating part. The local response exists only in the heating region. The vertically propagating response exists in the far field as well as in the heating region. The thermally forced vertically propagating response can be conceptualized as a response to an “equivalent topography,” the height of which is proportional to the intensity and zonal scale of the heating, and inversely proportional to the strength of the zonal flow. Particular solutions forced by realistic summer heating fields reveal that, for weak westerlies, the height of the equivalent topography is much larger than that of the real topography, suggesting that heating is more important than topography in forcing the summer stationary waves in the subtropics. It is also found that Newtonian cooling has a significant effect on the structure of the thermally forced stationary waves.

Corresponding author address: Dr. Ping Chen, NOAA–CIRES Climate Diagnostics Center, Mail Code: R/CDC1, 325 Broadway, Boulder, CO 80303-3328.Email: pc@cdc.noaa.gov

Abstract

Analytical solutions of thermally forced stationary waves in a linear quasigeostrophic model are obtained. It is found that the zonal flow has a profound impact on the structure of the responses. The inviscid solutions on a resting basic state are the Sverdrup solutions that are confined to the heating region. The solutions on a westerly zonal flow are composed of a local and a vertically propagating part. The local response exists only in the heating region. The vertically propagating response exists in the far field as well as in the heating region. The thermally forced vertically propagating response can be conceptualized as a response to an “equivalent topography,” the height of which is proportional to the intensity and zonal scale of the heating, and inversely proportional to the strength of the zonal flow. Particular solutions forced by realistic summer heating fields reveal that, for weak westerlies, the height of the equivalent topography is much larger than that of the real topography, suggesting that heating is more important than topography in forcing the summer stationary waves in the subtropics. It is also found that Newtonian cooling has a significant effect on the structure of the thermally forced stationary waves.

Corresponding author address: Dr. Ping Chen, NOAA–CIRES Climate Diagnostics Center, Mail Code: R/CDC1, 325 Broadway, Boulder, CO 80303-3328.Email: pc@cdc.noaa.gov

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