QBO effects on the diurnal tide in the upper atmosphere

We report on a series of numerical experiments conducted with the global-scale wave model (GSWM) and designed to investigate the effects of the quasi-biennial oscillation (QBO) on the migrating diurnal tide. Our results indicate that the diurnal tidal response in the upper mesosphere and lower thermosphere (MLT) is significantly affected by the QBO in zonal mean zonal winds, but largely insensitive to the QBO in stratospheric ozone. We discuss the variable mean wind results in light of previous analytic attempts to describe the diurnal tide in the presence of mean winds and dissipation. Our calculations do not explain the interannual tidal variations observed by the High Resolution Doppler Interferometer (HRDI) on the Upper Atmosphere Research Satellite (UARS).