The Arctic vortex in March 2011: a dynamical perspective

Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in the polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in Apr...

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Bibliographic Details
Published in:Atmospheric Chemistry and Physics
Main Authors: Hurwitz, M. M., Newman, P. A., Garfinkel, C. I.
Format: Text
Language:English
Published: 2018
Subjects:
Online Access:https://doi.org/10.5194/acp-11-11447-2011
https://www.atmos-chem-phys.net/11/11447/2011/
Description
Summary:Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in the polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in April. La Niña conditions and the westerly phase of the quasi-biennial oscillation (QBO) were observed in March 2011. Though these conditions are generally associated with a stronger vortex in mid-winter, the respective cold anomalies do not persist through March. Therefore, the La Niña and QBO-westerly conditions cannot explain the observed cold anomalies in March 2011. In contrast, positive sea surface temperature anomalies in the North Pacific may have contributed to the unusually weak tropospheric wave driving and strong Arctic vortex in late winter 2011.