Simulation of the quasi-biennial oscillations of the zonal wind in the equatorial stratosphere: Part II. Atmospheric general circulation models

The problem of simulating quasi-biennial oscillations (QBOs) of zonal velocity in the equatorial stratosphere in atmospheric general circulation models is considered. In accordance with the results from Part I of this study on the basis of the models developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences (INM RAS), the possibility of implementing (in these models) mechanisms of QBO excitation through both the interaction of planetary waves with the mean flow and breaking of short gravity waves is investigated. A new high-resolution 2° × 2.5° × 80 version of the INM RAS model is designed, a climate simulation with the two 2° × 2.5° × 39 and 2° × 2.5° × 80 versions of the INM RAS model is briefly described, results of spectral analysis of equatorial wave activity are presented, and the QBO formation processes in these models are considered in detail. For the new 2° × 2.5° × 80 model, realistic QBOs of zonal wind are obtained as the result of the action of both mechanisms.