Mechanism of the Arctic oscillation excitation is unclear up to now. The hypothesis of the arctic oscillation external excitation by the zonal mean wind variations at intervals 15-20 days is considered in this investigation. Often these variations appear close to the pole in the troposphere and propagate to the lower latitudes and in the stratosphere, causing variations of the Arctic oscillation index and affecting the stratospheric Polar vortex dynamics. The zonal mean wind variations are caused by the largescale disturbances, which have approximately barotropic long Rossby wave structure.
Arctic and Antarctic oscillation; torsional variations; zonal speed; synoptic perturbations; polar vortex; mode; planet waves