Influence of the QBO and solar activity on interannual variability of the spring-time transition of stratosphere circulation

•The influence of solar activity on spring transition dates was investigated.•QBO helps to identify the solar signal in the stratosphere.•Early transition occurs because of high planetary waves activity.•Later transition forced by seasonal changes of the solar zenith angle.•Under high solar activity conditions break up dates and the Sun relation is stronger.

In this paper the influence of solar activity on variability of the springtime transition dates of stratospheric circulation is investigated. To detect the influence, the springtime transition and solar activity datasets were grouped according to the phases of the Quasi-Biennial Oscillation (QBO). It was obtained that there is a dependence of spring transition dates on solar activity. In case of dividing data on early and later spring transition, the stronger influence of solar signal is revealed at late spring transition. It was also shown that under high solar activity conditions, the relation between spring transition dates and solar activity is stronger than at low one.