The episode of Quasi-Biennial Oscillation in 2016 did not have its roots in its distant past; the role of the strong El Ni\~no event

Abstract

We explore the anomalous behavior of the equatorial quasi-biennial oscillation (QBO) in zonal wind which it exhibited, since February 2016. In more detail, QBO interrupted its regular pattern and the eastward stratospheric winds unexpectedly reversed to a westward direction. We focus on the temporal evolution of the equatorial zonal wind in the altitude region 70 - 10 hPa, investigating particularly whether this unprecedented event could be considered as a result of scaling effect in the equatorial zonal wind. Furthermore, the link between the QBO abnormal behaviour in 2016 with the strong El Ni\~no event is investigated.