Do strong warm ENSO events control the phase of the stratospheric QBO?

Although there in general are no significant long-term correlations between the quasi-biennial oscillation (QBO) and the El Nino-Southern Oscillation (ENSO) in observations, we find that the QBO and the ENSO were aligned in the 3 to 4years after the three warm ENSO events in 1982, 1997, and 2015. We investigate this indicated relationship with a version of the EC-Earth climate model which includes nonorographic gravity waves. We analyze the modeled QBO in ensembles forced with climatological sea surface temperatures (SSTs) and observed SSTs. In the ensemble with observed SSTs we find a strong and significant alignment of the ensemble members in the equatorial stratospheric winds in the 2 to 4years after the strong ENSO event in 1997. This alignment also includes the observed QBO. No such alignment is found in the ensemble with climatological SSTs. These results indicate that strong warm ENSO events can lock the phase of the QBO.