Content - Quasi-Biennial Oscillation

QBOi – Towards Improving the Quasi-Biennial Oscillation in Global Climate Models

Activity Leaders

Scott Osprey
NCAS, University of Oxford, UK

Neal Butchart
Hadley Centre, UK

Kevin Hamilton

James Anstey
CCCMA, Canada


Charles McLandress, University of Toronto, Canada 

George Boer, CCCMA, Canada

Norm McFarlane, CCCMA, Canada

John Scinocca, CCCMA, Canada

Michael Sigmond, CCCMA, Canada

Bo Christiansen, DMI, Denmark

Shuting Yang, DMI, Denmark 

Albert Hertzog, LMD, France

Francois Lott, LMD, France

Riwal Plougonven, LMD, France

Peter Braesicke, KIT, Germany

Elisa Manzini, MPI, Germany

Hauke Schmidt, MPI, Germany

Chiara Cagnazzo, CMCC, Italy

Yoshio Kawatani, JAMSTEC, Japan

Shingo Watanabe, JAMSTEC, Japan

Shigeo Yoden, University of Kyoto, Japan

Hye Yeong-Chun, Yonsei University, Korea

Young-Ha Kim, Yonsei University, Korea

Tim Stockdale, ECMWF, UK 

Mark Baldwin, University of Exeter, UK 

Andrew Bushell, Met Office 

Adam Scaife, Met Office Hadley Centre, UK  

Lesley Gray, NCAS, University of Oxford, UK  

Verena Schenzinger, University of Oxford, UK  

Christiane Jablonowski, University of Michigan, USA 

Alan Plumb, MIT, USA

Julio Bacmeister, NCAR, USA 

Rolando Garcia, NCAR, USA 

Hanli Liu, NCAR, USA 

Jadwiga Richter, NCAR, USA 

Anne Smith, NCAR, USA 

Tim Dunkerton, NWRA, USA 

Marv Geller, Stony Brook, USA

David Rind, NASA-GISS, USA

Kohei Yoshida, MRI, Japan

Federico Serva, CMCC, Italy

Javier Garcia-Serrano, BSC-CNS, Spain

Laura Holt, NWRA, USA

Pu Lin, Princeton, USA

Isla Simpson, NCAR, USA

Jack Chen, NCAR, USA

Activity description

Until recently, only a small number of global climate models have successfully captured realistic tropical stratosphere variability. The most conspicuous manifestation of this variability is the quasi-biennial oscillation – known to have the longest naturally occurring timescale within the climate system. This tropical phenomenon is important to the redistribution of minor trace gas species involved in ozone chemistry and teleconnections linked with high latitude weather. 

Of the climate models participating in the Chemistry-Climate Model Validation Activity Phase 2, only two reported an internally generated QBO, seven chose nudging toward observations, while the remainder had no realistic QBO variability. Furthermore, in the recent WCRP Coupled Model Intercomparison Project - Phase 5 (CMIP5), only three models captured a realistic QBO. In a recent study exploring the effects of future climate change on tropical stratosphere variability, Kawatani and Hamilton (2013) reported a weakening of the QBO amplitude into the 21st Century. This result was consistent with increased tropical upwelling following a strengthening of the Brewer-Dobson circulation. However, no robust response was found for projected changes to the QBO period.

The objective of QBOi is to improve the fidelity of tropical stratosphere variability in present-day GCMs. This will be achieved by: (1) evaluating past and present-day modelled QBO variability and (2) soliciting the participation of modelling groups to design numerical experiments to explore the sensitivity dependencies of tropical stratosphere variability in current GCMs. Examples of these dependencies include details such as vertical resolution, wave parameterisations, etc. Our intention is that this will provide a ‘recipe book’ for simulating a reliable QBO, informing models contributing to future CMIP experiments and for numerical weather forecasters.

QBOi is focussed on modelling studies, but benefits from other SPARC activities, such as: Gravity Waves (for constraining parameter estimates within GCMs) and the Data Assimilation Working Group project S-RIP: SPARC Reanalysis/Analysis Intercomparison Project (providing wave climatologies). Output from QBOi will also benefit programmes such as the Working Group for Numerical Experimentation (evaluating process uncertainty), the Working Group on Seasonal to Interannual Prediction (identifying pathways for predictability), and within SPARC, CCMI (tracer transport) and DynVar (stratosphere-troposphere coupling).

During phase 1, a workshop was held to agree on a set of coordinated multi-model experiments and essential diagnostics (QBO Modelling and Reanalysis Workshop, 16-18 March 2015, Victoria, Canada). Progress was made toward agreeing a table of QBO metrics for future studies. The common set of experiments and diagnostics have subsequently been finalised and published on the QBOi project web page (see below).

Phase 2 will involve the completion of the first set of experiments, with a second workshop (Oxford, 26-30 September 2016) where first results will be reported and scoping for further experiments will be carried out, also emphasising QBO impacts and teleconnections.

The tangible deliverables for the project include peer-reviewed papers from participating groups.

Published results

Journal publications:

Osprey, S. M., N. Butchart, J. R. Knight, A. Scaife, K. Hamilton, J. A. Anstey, V. Schenzinger, and C. Zhang, 2016: An unexpected disruption of the atmospheric quasi-biennial oscillation. Science, 08 Sep 2016, DOI: 10.1126/science.aah4156

Rajendran K., I. M. Moroz, P. L. Read and S. M. Osprey, 2016: Synchronisation of the equatorial QBO by the annual cycle in tropical upwelling in a warming climate. Q. J. R. Meteorol. Soc., DOI: 10.1002/qj.2714

Hamilton, K., S. Osprey, and N. Butchart, 2015: Modeling the stratosphere’s “heartbeat,” EOS, 96, doi:10.1029/2015EO032301.

SPARC activity updates:

SPARC newsletter No. 45, 2015, p. 19: Report on the 1st QBO Modelling and Reanalyses Workshop, by Anstey, J., K. Hamilton, S. Osprey, N. Butchart, and L. Gray

Website for further information