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

  • Hide, R., 1969: Dynamics of the atmospheres of the major planets. J. Atmos. Sci, 26 , 841853.

  • Highwood, E. J., , and B. J. Hoskins, 1998: The tropical tropopause. Quart. J. Roy. Meteor. Soc, 124 , 15791604.

  • Holton, J. R., , P. H. Haynes, , M. E. McIntyre, , A. R. Douglass, , R. B. Rood, , and L. Pfister, 1995: Stratosphere–troposphere exchange. Rev. Geophys, 33 , 403439.

    • Search Google Scholar
    • Export Citation
  • Kerr-Munslow, A. M., , and W. A. Norton, 2006: Tropical wave driving of the annual cycle in tropical tropopause temperatures. Part I: ECMWF analyses. J. Atmos. Sci, 63 , 14101419.

    • Search Google Scholar
    • Export Citation
  • Kraucunas, I. P., , and D. L. Hartmann, 2005: Equatorial superrotation and the factors controlling the zonal-mean winds in the tropical upper troposphere. J. Atmos. Sci, 62 , 371389.

    • Search Google Scholar
    • Export Citation
  • Newell, R. E., , and S. Gould-Stewart, 1981: A stratospheric fountain? J. Atmos. Sci, 38 , 27892796.

  • Norton, W. A., 2003: Sensitivity of northern hemisphere surface climate to simulation of the stratospheric polar vortex. Geophys. Res. Lett, 30 .1627, doi:10.1029/2003GL016958.

    • Search Google Scholar
    • Export Citation
  • Pope, V. D., , M. L. Gallani, , P. R. Rowntree, , and R. A. Stratton, 2000: The impact of new physical parametrizations in the Hadley Centre climate model—HadAM3. Climate Dyn, 16 , 123146.

    • Search Google Scholar
    • Export Citation
  • Sardeshmukh, P. D., , and B. J. Hoskins, 1987: On the derivation of the divergent flow from the rotational flow: The χ problem. Quart. J. Roy. Meteor. Soc, 113 , 339360.

    • Search Google Scholar
    • Export Citation
  • Sardeshmukh, P. D., , and B. J. Hoskins, 1988: The generation of global rotational flow by steady idealized tropical divergence. J. Atmos. Sci, 45 , 12281251.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., , G. W. Branstator, , D. Karoly, , A. Kumar, , N-C. Lau, , and C. Ropelewski, 1998: Progress during TOGA in understanding and modeling global teleconnections associated with tropical sea surface temperatures. J. Geophys. Res, 103 , 1429114324.

    • Search Google Scholar
    • Export Citation
  • van Loon, H., , and R. L. Jenne, 1970: The annual wave in the temperature of the lower stratosphere. J. Atmos. Sci, 27 , 701705.

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Tropical Wave Driving of the Annual Cycle in Tropical Tropopause Temperatures. Part II: Model Results

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  • 1 NCAS Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, Reading, United Kingdom
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Abstract

The atmospheric response to a localized distribution of tropical heating is examined in terms of the stationary waves excited and how these impact the mean flow near the tropical tropopause. This is done by examining nonlinear simulations of the Gill model with a primitive equation model that extends from the surface up into the stratosphere. The model produces strong cooling of zonal mean temperatures near the tropical tropopause when the heating is on the equator but weaker cooling with the heating at 15°N. The model shows that equatorial Rossby waves that penetrate the lower stratosphere and changes in EP flux divergence that correspond to the observed changes between December and August. It is suggested that ascent in the upper tropical troposphere is driven by vorticity advection or equivalently potential vorticity fluxes due to these equatorial Rossby waves, particularly when the heating is close to the equator. The model results provide support to the hypothesis that the annual cycle in tropical tropopause temperatures is a result of the annual variation in latitude of tropical heating and that equatorial Rossby waves are key in producing the response in the upper troposphere and lower stratosphere.

Corresponding author address: Dr. W. A. Norton, NCAS Centre for Global Atmospheric Modelling, Dept. of Meteorology, University of Reading, Reading RG6 6BB, United Kingdom. Email: W.A.Norton@reading.ac.uk

Abstract

The atmospheric response to a localized distribution of tropical heating is examined in terms of the stationary waves excited and how these impact the mean flow near the tropical tropopause. This is done by examining nonlinear simulations of the Gill model with a primitive equation model that extends from the surface up into the stratosphere. The model produces strong cooling of zonal mean temperatures near the tropical tropopause when the heating is on the equator but weaker cooling with the heating at 15°N. The model shows that equatorial Rossby waves that penetrate the lower stratosphere and changes in EP flux divergence that correspond to the observed changes between December and August. It is suggested that ascent in the upper tropical troposphere is driven by vorticity advection or equivalently potential vorticity fluxes due to these equatorial Rossby waves, particularly when the heating is close to the equator. The model results provide support to the hypothesis that the annual cycle in tropical tropopause temperatures is a result of the annual variation in latitude of tropical heating and that equatorial Rossby waves are key in producing the response in the upper troposphere and lower stratosphere.

Corresponding author address: Dr. W. A. Norton, NCAS Centre for Global Atmospheric Modelling, Dept. of Meteorology, University of Reading, Reading RG6 6BB, United Kingdom. Email: W.A.Norton@reading.ac.uk

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