An unexpected disruption of the atmospheric quasi-biennial oscillation.
One of the most repeatable phenomena seen in the atmosphere, the quasi-biennial oscillation (QBO) between prevailing eastward and westward wind jets in the equatorial stratosphere (approximately 16 to 50 kilometers altitude), was unexpectedly disrupted in February 2016. An unprecedented westward jet formed within the eastward phase in the lower stratosphere and cannot be accounted for by the standard QBO paradigm based on vertical momentum transport. Instead, the primary cause was waves transporting momentum from the Northern Hemisphere. Seasonal forecasts did not predict the disruption, but analogous QBO disruptions are seen very occasionally in some climate simulations. A return to more typical QBO behavior within the next year is forecast, although the possibility of more frequent occurrences of similar disruptions is projected for a warming climate.
National Centre for Atmospheric Science (NCAS)-Climate, University of Oxford, Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK. scott.osprey@physics.ox.ac.uk.
Scott M
SM
Osprey
Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB, UK.
Neal
N
Butchart
Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB, UK.
Jeff R
JR
Knight
Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB, UK. Department of Mathematics and Computer Science, University of Exeter, Exeter, UK.
Adam A
AA
Scaife
International Pacific Research Center, University of Hawai`i, Honolulu, USA.
Kevin
K
Hamilton
Canadian Centre for Climate Modelling and Analysis, University of Victoria, Victoria, British Columbia, Canada.
James A
JA
Anstey
National Centre for Atmospheric Science (NCAS)-Climate, University of Oxford, Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
Verena
V
Schenzinger
International Pacific Research Center, University of Hawai`i, Honolulu, USA.
Chunxi
C
Zhang