Interactions between the stratosphere, the sun and the QBO during the northern summer

We have shown in a number of papers that a large part of the variability of the temperatures observed especially in the tropical stratosphere is correlated with the 11-year sunspot cycle. In our analyses we stratified the data according to the phase of the QBO (Quasi-Biennial Oscillation) and we got very clear correlations between the stratified temperatures in the stratosphere and the 11-year solar cycle. Our results, mainly given as the difference between solar maxima and minima, show a large influence of the 11-year solar cycle on the temperatures and geopotential heights of the lower and middle stratosphere, and on the equatorial QBO. With the new data since 2003 we can prolong our data series by 8 years, that is by one weak solar maximum and a deep solar minimum. These new data fully confirm our earlier results.

► We present an update of the solar signal in the stratosphere during July. ► The modulation of the solar signal by the QBO can be confirmed for the last solar cycle. ► We can identify a reduced QBO amplitude during solar maximum.