Abstract
3-dimensional numerical nonlinear model of general circulation of the middle and upper atmosphere (MUAM) is used to investigate reaction of the atmospheric circulation in the middle and upper atmosphere to changes in phases of equatorial stratospheric quasi-biennial oscillation (QBO). To estimate changes in transport of atmospheric gas species, residual meridional circulation (RMC) is calculated based on the modelled atmospheric hydrodynamic fields for easterly, westerly and transitional (so-called “easterly-shear” and “westerly-shear”) QBO phases. For this purpose, four 10-members ensembles of MUAM simulations have been obtained corresponding to the aforementioned QBO phases. To determine QBO phases, empirical orthogonal functions (EOF) are applied for the equatorial zonal wind profiles. Statistically significant results are obtained illustrating how changes in direction of equatorial stratospheric winds influence extratropical circulation. It is shown in particularly, that the strongest changes in thermal and dynamical conditions of the middle- and high-latitude stratosphere-mesosphere occur during easterly-shear QBO phase.
Published Version
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