The impact of radiative forcing on the equatorial stratospheric circulation

Abstract

The aim of this work is to evaluate how the Quasi-Biennial Oscillation (QBO), which dominates interannual variability in the tropical stratosphere, responds to different radiative forcings in the EC-EARTH climate model version 3.3. Two sets of simulations have been used, consisting in three atmosphere-only and three atmosphere-ocean coupled experiments, which are based on past, present and future conditions. The QBO influence on the extratropical circulation, formally known as the Holton-Tan effect, has also been assessed during boreal winter (DJF). Results show a notorious shortening of the QBO period and a clear weakening of the QBO amplitude under a warming climate in the coupled simulations; which do not show a significant impact on the Holton-Tan effect in the polar vortex.