In this study we examine the 2016 disruption of the Quasi-Biennial Oscillation (QBO) using fixed system model-based products including the 1980 to the current year/month MERRA-2 high resolution atmospheric reanalysis. The disruption was of particular interest, aside from its magnitude, by it not being identified by any operational forecast model (as well, not being spontaneously produced by a majority of the CMIP5 class of models). We examine features that make the event distinct in the half century of its otherwise regular oscillatory behaviour, and the atmospheric state in the build up to it, and its recovery in the following cycle.

Of great interest is the impact and response of the QBO, and its disruption, to features in the troposphere and at the surface through extratropical teleconnections. For example, it is believed that El Niño and the Arctic sea ice may have played a more than minor role in disrupting tropospheric waves that transmit vertically and dissipate within the stratosphere, along with other known and unknown periodic and trending climate factors.

Although the current CAFÉ modelling system does not have its own spontaneous QBO, it is anticipated that its forced QBO through the assimilation to the JRA55 reanalysis may offer some insight into the variability and predictability of QBO, in addition to large ensemble experiments initiated from optimised initial states performed and underway.