This work was supported by the research programme of the U.K. Met Office. C. D. Warner received support from the Natural Environment Research Council through Grant NER/A/S/2000/00452. We thank C. Souprayen at the Service d’Aeronomie for the radiosonde data used to compile the azimuthal sector plots in Figs. 1 and 2. We thank three anonymous reviewers for their suggestions, which have led to important improvements to this paper.
Alexander, M. J., 1998: Interpretations of observed climatological patterns in stratospheric gravity wave variance. J. Geophys. Res., 103 , 8627–8640.
Alexander, M. J., , and T. J. Dunkerton, 1999: A spectral parameterization of mean-flow forcing due to breaking gravity waves. J. Atmos. Sci., 56 , 4167–4182.
Alexander, M. J., , and R. A. Vincent, 2000: Gravity waves in the tropical lower stratosphere: A model study of seasonal and interannual variability. J. Geophys. Res., 105 , 17983–17993.
Beres, J. H., , M. J. Alexander, , and J. R. Holton, 2002: Effects of tropospheric wind shear on the spectrum of convectively generated gravity waves. J. Atmos. Sci., 59 , 1805–1824.
Butchart, N., , J. Austin, , J. R. Knight, , A. A. Scaife, , and M. L. Gallani, 2000: The response of the stratospheric climate to projected changes in well-mixed greenhouse gases from 1992 to 2051. J. Climate, 13 , 2142–2159.
Charron, M., , and E. Manzini, 2002: Gravity waves from fronts: Parameterization and middle atmosphere response in a general circulation model. J. Atmos. Sci., 59 , 923–941.
Dunkerton, T. J., , and N. Butchart, 1984: Propagation and selective transmission of internal gravity waves in a sudden warming. J. Atmos. Sci., 41 , 1443–1460.
Fritts, D. C., , and W. Lu, 1993: Spectral estimates of gravity wave energy and momentum fluxes II: Parameterization of wave forcing and variability. J. Atmos. Sci., 50 , 3695–3713.
Fritts, D. C., , and T. E. VanZandt, 1993: Spectral estimates of gravity wave energy and momentum fluxes I: Energy dissipation, acceleration and constraints. J. Atmos. Sci., 50 , 3685–3694.
Gregory, D., , and P. R. Rowntree, 1990: A mass flux convection scheme with representation of cloud ensemble characteristics and stability-dependent closure. Mon. Wea. Rev., 118 , 1483–1506.
Gregory, D., , G. J. Shutts, , and J. R. Mitchell, 1998: A new gravity-wave-drag scheme incorporating anisotropic orography and low-level wave breaking: Impact upon the climate of the UK Meteorological Office Unified Model. Quart. J. Roy. Meteor. Soc., 124 , 463–493.
Hines, C. O., 1997: Doppler spread parameterization of gravity wave momentum deposition in the middle atmosphere. Part 1: Basic formulation. J. Atmos. Terr. Phys., 59 , 371–386.
Holton, J. R., 1982: The role of gravity wave-induced drag and diffusion in the momentum budget of the mesosphere. J. Atmos. Sci., 39 , 791–799.
Lawrence, B. N., 1997: Some aspects of the sensitivity of stratospheric climate simulation to model lid height. J. Geophys. Res., 102 , 23805–23811.
McFarlane, N. A., 1987: The effect of orographically excited gravity wave drag on the general circulation of the lower stratosphere and troposphere. J. Atmos. Sci., 44 , 1775–1800.
Medvedev, A. S., , and G. P. Klaassen, 1999: Parameterization of gravity wave momentum deposition based on nonlinear wave interactions: Basic formulation and sensitivity tests. J. Atmos. Terr. Sol. Phys., 62 , 1015–1033.
Palmer, T. N., , G. J. Shutts, , and R. Swinbank, 1986: Alleviation of a systematic westerly bias in general circulation and numerical weather prediction models through an orographic wave drag parameterisation. Quart. J. Roy. Meteor. Soc., 112 , 1001–1039.
Ray, E. A., , J. R. Holton, , E. F. Fishbein, , L. Froidevaux, , and J. W. Waters, 1994: The tropical semiannual oscillations in temperature and ozone as observed by the MLS. J. Atmos. Sci., 51 , 3045–3052.
Ricciardulli, L., , and R. Garcia, 2000: The excitation of equatorial waves by deep convection in the NCAR Community Climate Model (CCM3). J. Atmos. Sci., 57 , 3461–3484.
Sato, K., , and T. J. Dunkerton, 1997: Estimates of momentum flux associated with equatorial Kelvin and gravity waves. J. Geophys. Res., 102 , 26247–26261.
Scaife, A. A., , N. Buchart, , C. D. Warner, , D. Stainforth, , W. Norton, , and J. Austin, 2000: Realistic quasi-biennial oscillations in a simulation of the global climate. Geophys. Res. Lett., 27 , 3481–3484.
Scaife, A. A., , N. Buchart, , C. D. Warner, , and R. Swinbank, 2002: Impact of a spectral gravity parameterization on the stratosphere in the Met Office Unified Model. J. Atmos. Sci., 59 , 1473–1489.
Warner, C. D., , and M. E. McIntyre, 1996: On the propagation and dissipation of gravity wave spectra through a realistic middle atmosphere. J. Atmos. Sci., 53 , 3213–3235.
Warner, C. D., , and M. E. McIntyre, 1999: Toward an ultra-simple spectral gravity wave parameterization for general circulation models. Earth Planets Space, Vol. 51, Terra Scientific, 475–484.
Warner, C. D., , and M. E. McIntyre, 2001: An ultrasimple spectral gravity wave parameterization for nonorographic gravity waves. J. Atmos. Sci., 58 , 1837–1857.