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Quasibiennial oscillations in North-South solar asymmetry

If the oscillations of the sunspot numbers themselves are not an indicator for the stratospheric quasibiennial oscillations, maybe such an indicator are the oscillations of sunspot asymmetry. To check this, a spectral analysis of asymmetry was made using a time series with the same length and covering the same interval, the same filtering procedure and moving normal window. The results are presented in Table 2.

Table 2

In the whole interval studied (January 1953 - December 1998), the prevailing periodicity in solar asymmetry is 25.6 months, and the peaks in stratospheric winds QBO lie within 0.7 of the amplitude of the asymmetry QBO peaks. So it seems more probable that if the oscillations in stratospheric winds are in some way or another related to the Sun, the parameter responsible for such an influence is the solar asymmetry rather than the level of the solar activity itself.