Spectral characteristics of quasi-biennial oscillations of the equatorial stratospheric wind and the problem of synchronization

Structural stability of quasi-biennial oscillations of zonal wind in the equatorial stratosphere

“…This problem primarily relates not to the wave parameters, whose role has been studied in sufficient detail in [3,4], but to the parameters determining the vertical diffusion and vertical transport. The significance of the process of vertical diffusion was also pointed in [1,5]. The problem of determination of the key parameters is closely related to the problem of structural stability of QBO, which is the subject of this paper.…”

“…The first problem relates to the synchronization of QBO with the semiannual oscillations (SAO) of the zonal wind velocity in the upper stratosphere and the mesosphere. In [5], based on the analysis of the period variability and other characteristics of QBO, we have shown that there exists a certain synchronization of QBO and SAO (and possibly the annual cycle too). The QBO and SAO should be considered as an integrated circulation system of the equatorial upper atmosphere.…”

“…Since the main mechanism of QBO formation is, as has been noted above, the interaction of planetary waves with the mean zonal flow, for modelling this interaction we take the model proposed by Plumb [6] and used in our papers [3,5]. We modify this model by introducing the variable coefficient of vertical diffusion and the term describing the vertical transport.…”

“…For the sake of simplicity, the wave forcing is considered as two symmetric waves with opposite directions. The equation for the evolution of the mean (averaged over the zone) zonal velocity u has the following form [5,6]:…”

Stratosphere-troposphere interactions

“…Problems of QBO struc tural stability and synchronization with various peri odical processes (the Sun's annual cycle, the equato rial wind's semi annual oscillations, etc.) were stud ied, and the decisive role of planetary waves in the formation of the cycle's main period was shown, as well as the important role of short waves in QBO energy transmission and synchronization and in the semi annual mesospheric cycle [25].…”