• Andrews, D. G., J. R. Holton, and C. B. Leovy, 1987: Middle Atmosphere Dynamics. Academic Press, 489 pp.

  • Bergman, J. W., and M. L. Salby, 1994: Equatorial wave activity derived from fluctuations in observed convection. J. Atmos. Sci.,51, 3791–3806.

  • Boville, B. A., and W. J. Randel, 1992: Equatorial waves in a stratospheric GCM: Effects of vertical resolution. J. Atmos. Sci.,49, 785–801.

  • Dunkerton, T. J., 1991: Nonlinear propagation of zonal winds in an atmosphere with Newtonian cooling and equatorial wavedriving. J. Atmos. Sci.,48, 236–263.

  • ——, 1997: The role of gravity waves in the quasi-biennial oscillation. J. Geophys. Res.,102(D22), 26053–26076.

  • ——, and D. P. Delisi, 1985: Climatology of the equatorial lower stratosphere. J. Atmos. Sci.,42, 376–396.

  • Fels, S. B., 1982: A parameterization of scale-dependent radiative damping rates in the middle atmosphere. J. Atmos. Sci.,39, 1141–1152.

  • Hamilton, K., 1984: Mean wind evolution through the quasi-biennial cycle in the tropical lower stratosphere. J. Atmos. Sci.,41, 2113–2125.

  • Hayashi, Y., 1976: Non-singular resonance of equatorial waves under the radiation condition. J. Atmos. Sci.,33, 183–201.

  • ——, 1982: Space-time spectral analysis and its application to atmospheric waves. J. Meteor. Soc. Japan,60, 156–171.

  • ——, and D. G. Golder, 1994: Kelvin and mixed Rossby–gravity waves appearing in the GFDL “SKYHI” general circulation model and the FGGE dataset: Implications for their generation mechanism and role in the QBO. J. Meteor. Soc. Japan,72, 901–935.

  • ——, ——, and J. D. Mahlman, 1984: Stratospheric and mesospheric Kelvin waves simulated by the GFDL “SKYHI” general circulation model. J. Atmos. Sci.,41, 1971–1984.

  • Hess, P. G., H. H. Hendon, and D. S. Battisti, 1993: The relationship between mixed Rossby–gravity waves and convection in a general circulation model. J. Meteor. Soc. Japan,71, 321–338.

  • Holton, J. R., and R. S. Lindzen, 1972: An updated theory for the quasi-biennial cycle of the tropical stratosphere. J. Atmos. Sci.,29, 1076–1080.

  • Horinouchi, T., and S. Yoden, 1996: Wave excitation by localized heating in the tropics and its propagation into the middle atmosphere. J. Meteor. Soc. Japan,74, 189–210.

  • Lindzen, R. S., and J. R. Holton, 1968: A theory of the quasi-biennial oscillation. J. Atmos. Sci.,25, 1095–1107.

  • ——, and C.-Y. Tsay, 1975: Wave structure of the tropical stratosphere over the Marshall Islands area during 1 April–1 July 1958. J. Atmos. Sci.,32, 2008–2021.

  • Madden, R. A., and P. R. Julian, 1972: Description of global-scale circulation cells in the tropics with a 40–50 day period. J. Atmos. Sci.,29, 1109–1123.

  • Magaña, V., and M. Yanai, 1995: Mixed Rossby–gravity waves triggered by lateral forcing. J. Atmos. Sci.,52, 1473–1486.

  • Mahlman, J. D., and L. J. Umshied, 1984: Dynamics of the middle atmosphere: Successes and problems of the GFDL “SKYHI” general circulation model. Dynamics of the Middle Atmosphere, J. R. Holton and T. Matsuno, Eds., Terra Scientific, 501–525.

  • Maruyama, T., 1994: Upward transport of westerly momentum due to disturbances of the equatorial lower stratosphere in the period range of about 2 days—A Singapore data analysis for 1983–1993. J. Meteor. Soc. Japan,72, 423–432.

  • Mote, P. W., and Coauthors, 1996: An atmospheric tape recorder: The imprint of tropical tropopause temperatures on stratospheric water vapor. J. Geophys. Res.,101, 3989–4006.

  • Nakazawa, T., 1988: Tropical super clusters within intraseasonal variations over the western Pacific. J. Meteor. Soc. Japan,66, 823–839.

  • Naujokat, B., 1986: An update of the observed quasi-biennial oscillation of the stratospheric winds over the tropics. J. Atmos. Sci.,43, 1873–1877.

  • Nishi, N., and A. Sumi, 1995: Eastward-moving disturbance near the tropopause along the equator during the TOGA COARE IOP. J. Meteor. Soc. Japan,73, 321–337.

  • Ogino, S., M. D. Yamanaka, and S. Fukao, 1995: Meridional variation of lower stratospheric gravity wave activity: A quick look at Hakuho-Maru J-COARE cruise rawinsonde data. J. Meteor. Soc. Japan,73, 407–413.

  • Peixoto, J. P., and A. H. Oort, 1992: Physics of Climate. American Institute of Physics, 520 pp.

  • Pfister, L., S. Scott, M. Loewenstein, S. Bowen, and M. Legg, 1993a:Mesoscale disturbances in the tropical stratosphere excited by convection: Observations and effects on the stratospheric momentum budget. J. Atmos. Sci.,50, 1058–1075.

  • ——, K. R. Chan, T. P. Bui, S. Bowen, M. Legg, B. Gary, K. Kelly, M. Proffitt, and W. Starr, 1993b: Gravity waves generated by a tropical cyclone during the STEP tropical field program: A case study. J. Geophys. Res.,98, 8611–8638.

  • Plumb, R. A., 1977: The interaction of two internal waves with the mean flow: Implications for the theory of the quasi-biennial oscillation. J. Atmos. Sci.,34, 1847–1858.

  • ——, and A. D. McEwan, 1978: The instability of a forced standing wave in a viscous stratified fluid: A laboratory analogue of the quasi-biennial oscillation. J. Atmos. Sci.,35, 1827–1839.

  • ——, and R. C. Bell, 1982: A model of the quasi-biennial oscillation on an equatorial beta plane. Quart. J. Roy. Meteor. Soc.,108, 335–352.

  • Salby, M. L., and R. R. Garcia, 1987: Transient response to localized episodic heating in the tropics. Part I: Excitation and short-time near field behavior. J. Atmos. Sci.,44, 458–498.

  • Saravanan, R., 1990: A multiwave model of the quasi-biennial oscillation. J. Atmos. Sci.,47, 2465–2474.

  • Sato, K., and T. J. Dunkerton, 1997: Estimates of momentum flux associated with equatorial Kelvin and gravity waves. J. Geophys. Res.,102 (D22), 26247–26261.

  • ——, F. Hasegawa, and I. Hirota, 1994: Short-period disturbances in the equatorial lower stratosphere. J. Meteor. Soc. Japan,72, 859–872.

  • Takahashi, M., 1996: Simulation of the stratospheric quasi-biennial oscillation using a general circulation model. Geophys. Res. Lett.,23, 661–664.

  • ——, and B. A. Boville, 1992: A three-dimensional simulation of the equatorial quasi-biennial oscillation. J. Atmos. Sci.,49, 1020–1035.

  • ——, and T. Kumakura, 1995: Equatorial wave behavior in a three-dimensional sector model: Relation to the simulated QBO-like oscillation and comparison with a T21 general circulation model. J. Meteor. Soc. Japan,73, 1011–1027.

  • ——, and M. Shiobara, 1995: A note on a QBO-like oscillation in a 1/5 sector three-dimensional model derived from a GCM. J. Meteor. Soc. Japan,73, 131–137.

  • ——, N. Zhao, and T. Kumakura, 1997: Equatorial waves in a general circulation model simulating a quasi-biennial oscillation. J. Meteor. Soc. Japan,75, 529–540.

  • Takayabu, Y. N., 1994a: Large-scale cloud disturbances associated with equatorial waves. Part I: Spectral features of the cloud disturbances. J. Meteor. Soc. Japan,72, 433–449.

  • ——, 1994b: Large-scale cloud disturbances associated with equatorial waves. Part II: Westward-propagating inertio-gravity waves. J. Meteor. Soc. Japan,72, 451–465.

  • Tsuda, T., Y. Murayama, H. Wiryosumarto, S. W. B. Harijono, and S. Kato, 1994a: Radiosonde observations of equatorial atmosphere dynamics over Indonesia. Part 1: Equatorial waves and diurnal tides. J. Geophys. Res.,99, 10491–10505.

  • ——, ——, ——, ——, and S. Kato, 1994b: Radiosonde observations of equatorial atmosphere dynamics over Indonesia. Part II: Characteristics of gravity waves. J. Geophys. Res.,99, 10507–10516.

  • Wallace, J. M., and V. E. Kousky, 1968: Observational evidence of Kelvin waves in the tropical stratosphere. J. Atmos. Sci.,25, 900–907.

  • Yanai, M., and T. Maruyama, 1966: Stratospheric wave disturbances propagating over the equatorial Pacific. J. Meteor. Soc. Japan,44, 291–294.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 104 104 4
PDF Downloads 12 12 1

Wave–Mean Flow Interaction Associated with a QBO-like Oscillation Simulated in a Simplified GCM

View More View Less
  • 1 Department of Geophysics, Kyoto University, Kyoto, Japan
© Get Permissions
Restricted access

Abstract

The interaction between convectively excited waves and the mean zonal wind in the equatorial lower stratosphere is investigated with a simplified general circulation model (GCM). The model has T42 truncation, and the vertical resolution is about 700 m in the stratosphere. Although it is an “aquaplanet” model with uniform sea surface temperature, cumulus convection in low latitudes has realistic hierarchical structures with reasonable space–time spectral distributions. The model produced an oscillation having quite similar features to the equatorial quasi-biennial oscillation (QBO), although the period is 400 days.

Waves in the equatorial lower stratosphere of the model are excited mainly by the cumulus convection in low latitudes. The energy of these waves is a little larger than that observed in the real atmosphere. The dominant waves are gravity waves having an equivalent depth of about 200 m and those of 40–100 m. About half of the transport and deposition of zonal momentum contributing to the oscillation is accounted for by the gravest symmetric gravity modes: eastward momentum by Kelvin waves and westward momentum by n = 1 gravity waves. The momentum deposition is done over a wide range of zonal wavenumber (2–30), while about half of it is done over a period of 1–3 days. The deposition has rather continuous phase speed distributions and a considerable portion of it is provided by waves having critical levels. Since gravity waves with small intrinsic phase speeds have small vertical wavelengths, vertical grid spacings of 700 m or less appear to be required in the lower stratosphere for GCMs in order to simulate the QBO.

* Current affiliation: Department of Atmospheric Sciences, University of Washington, Seattle, Washington.

Corresponding author address: Dr. Takeshi Horinouchi, Department of Atmospheric Sciences, University of Washington, Box 351640, Seattle, WA 98195.

Email: horinout@atmos.washington.edu.

Abstract

The interaction between convectively excited waves and the mean zonal wind in the equatorial lower stratosphere is investigated with a simplified general circulation model (GCM). The model has T42 truncation, and the vertical resolution is about 700 m in the stratosphere. Although it is an “aquaplanet” model with uniform sea surface temperature, cumulus convection in low latitudes has realistic hierarchical structures with reasonable space–time spectral distributions. The model produced an oscillation having quite similar features to the equatorial quasi-biennial oscillation (QBO), although the period is 400 days.

Waves in the equatorial lower stratosphere of the model are excited mainly by the cumulus convection in low latitudes. The energy of these waves is a little larger than that observed in the real atmosphere. The dominant waves are gravity waves having an equivalent depth of about 200 m and those of 40–100 m. About half of the transport and deposition of zonal momentum contributing to the oscillation is accounted for by the gravest symmetric gravity modes: eastward momentum by Kelvin waves and westward momentum by n = 1 gravity waves. The momentum deposition is done over a wide range of zonal wavenumber (2–30), while about half of it is done over a period of 1–3 days. The deposition has rather continuous phase speed distributions and a considerable portion of it is provided by waves having critical levels. Since gravity waves with small intrinsic phase speeds have small vertical wavelengths, vertical grid spacings of 700 m or less appear to be required in the lower stratosphere for GCMs in order to simulate the QBO.

* Current affiliation: Department of Atmospheric Sciences, University of Washington, Seattle, Washington.

Corresponding author address: Dr. Takeshi Horinouchi, Department of Atmospheric Sciences, University of Washington, Box 351640, Seattle, WA 98195.

Email: horinout@atmos.washington.edu.

Save