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Modulation of Antarctic vortex composition by the quasi‐biennial oscillation
Author(s) -
Strahan S. E.,
Oman L. D.,
Douglass A. R.,
Coy L.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl063759
Subject(s) - stratosphere , microwave limb sounder , quasi biennial oscillation , polar vortex , middle latitudes , atmospheric sciences , geology , ozone depletion , vortex , anomaly (physics) , southern hemisphere , climatology , breakup , northern hemisphere , environmental science , physics , meteorology , condensed matter physics , mechanics
Using a decade of Aura Microwave Limb Sounder observations, we show distinctly different N 2 O distributions in Southern Hemisphere winter that depend on the phase of the quasi‐biennial oscillation (QBO). Composites of the nitrous oxide (N 2 O) anomalies calculated for westerly and easterly phases show that QBO‐generated variability originating in the subtropical middle stratosphere fills the midlatitude surf zone by late winter. After the spring vortex breakup, the anomaly is transported to the Antarctic where it remains until the next vortex forms in fall. Trapped in the newly formed vortex, the anomaly descends in isolation through fall and winter, arriving in the Antarctic lower stratosphere in September—about 1 year after it formed. This transport pathway explains previously reported variability of N 2 O and inorganic chlorine (Cl y ) inside the Antarctic vortex and demonstrates that the middle stratosphere QBO affects ozone depletion by modulating Antarctic Cl y .