19 February 2020

Response of the Quasi‐Biennial Oscillation to a Warming Climate in Global Climate Models


The Quasi-biennial Oscillation (QBO) is the dominant mode of variability in the tropical stratosphere. The QBO directly impacts stratospheric temperature, water vapor, and ozone, and impacts tropospheric variability by modulating the stratospheric polar vortex and the Madden-Julian Oscillation (MJO). In this study, we examine how the QBO will likely change in a warming climate by examining its response to doubled and quadrupled CO2 in eleven general circulation models. 


QBO impacts the variability of the stratosphere and troposphere and is a source of seasonal predictability. Understanding how the QBO will change in a warming climate is important to understanding how stratospheric and tropospheric variability will change in the future.


We find that there is no consensus among climate models how the QBO period will change in the warming climate. In the quadrupled CO2 simulations, a reduction in the QBO period to 14 months was found in some models, whereas in several others the tropical oscillation completely disappeared. In contrast, all the models projected a decrease in the QBO amplitude in a warmer climate.

More research is needed on how large-scale tropical waves (Kelvin and mixed-Rossby GWs), as well as small scale gravity waves, will change in warming climate to assess how the QBO and its impacts will change in future climate.

Jadwiga Richter
National Center for Atmospheric Research (NCAR)
Richter, J, N Butchart, Y Kawatani, A Bushell, L Holt, F Serva, J Anstey, et al.  2020.  "Response of the Quasi‐Biennial Oscillation to a Warming Climate in Global Climate Models."  Quarterly Journal of the Royal Meteorological Society.  https://doi.org/10.1002/qj.3749.