Quasi‐decadal modulation of the influence of the equatorial quasi‐biennial oscillation on the north polar stratospheric temperatures

Low‐frequency variations, produced by stratifying north polar temperature data according to the phase of the equatorial quasi‐biennial oscillation, have been suggested by several authors to aliasing effects resulting from an undersampling. However, similar low‐frequency quasi‐decadal variations correlated with the solar cycle can be found by calculating a running correlation between the equatorial zonal winds and the north polar temperatures without decreasing the sampling frequency of the original signal. This clearly shows that the undersampling is not an essential feature of the present problem, but changes in the relationship between the equatorial and polar regions on the decadal time scale are fundamental aspects.