QBO: Quasi-Biennial Oscillation

QBO: Quasi-Biennial Oscillation
The quasi-biennial oscillation (QBO) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km (0.6 mi) per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found. (Wikipedia)

Please cite data sources, following the data providers' instructions
Dataset DOIs
None
Hosted Climate Index Files
None
Data Access
  1. The Quasi-Biennial-Oscillation Data Series (Freie U, Berlin)
  2. Climate Indices: Monthly Atmospheric and Ocen Time Series (NOAA ESRL/PSD)
Usage Restrictions
None

Cite this page

Acknowledgement of any material taken from or knowledge gained from this page is appreciated:

National Center for Atmospheric Research Staff (Eds). Last modified "The Climate Data Guide: QBO: Quasi-Biennial Oscillation.” Retrieved from https://climatedataguide.ucar.edu/climate-data/qbo-quasi-biennial-oscillation on 2025-08-28.


Citation of datasets is separate and should be done according to the data providers' instructions. If known to us, data citation instructions are given in the Data Access section, above.


Acknowledgement of the Climate Data Guide project is also appreciated:

Schneider, D. P., C. Deser, J. Fasullo, and K. E. Trenberth, 2013: Climate Data Guide Spurs Discovery and Understanding. Eos Trans. AGU, 94, 121–122, https://doi.org/10.1002/2013eo130001

Key Figures

Climate Data Guide Image: QBO

QBO for 1953-2012. Data source (Freie Universitat, Berlin)

Other Information

Earth system components and main variables
Atmosphere, Wind
Type of data product
Climate Indices, Circulation, QBO
Dataset collections
None

Years of record
to
Metadata ID
None
Data time period extended
Yes, data set is extended
Timestep
Monthly
Domain
Tropics
Formats:
ascii
Input Data
None
Vertical Levels:
Multiple levels
Missing Data Flag
Missing data present
Ocean or Land
None
Spatial Resolution
None
Model Resolution (reanalysis)
None
Data Assimilation Method
None
Model Vintage (reanalysis)
None

Key Publications
  1. Naujokat, B., 1986: An update of the observed quasi-biennial oscillation of the stratospheric winds over the tropics. J. Atmos. Sci., 43, 1873-1877.
  2. Baldwin, M.P. et al, 2001: The Quasi-Biennial Oscillation. Reviews of Geophys., 39, 179-229.
  3. Andrews, D.G., J.R. Holton, and C.B. Leovy, 1987: Middle Atmosphere Dynamics. Academic Press, 489pp