| Summary: | The effect of the Madden-Julian Oscillation (MJO) on springtime Antarctic ozone variations is revealed for the first time from multi-satellite reanalysis and model simulations. Twenty to 30 days after MJO Phase 8 (P8), Antarctic total column ozone (TCO) anomalies significantly decrease by up to -15 DU, associated with a wave-1 response at around 60 degrees S. After MJO P8, MJO-related geopotential height anomalies in the southern hemispheric (SH) Indian Ocean emanate from subtropics to polar regions, leading to suppressed upward and poleward propagation of planetary waves (PWs) and weakened Brewer-Dobson circulation in the SH stratosphere. This in turn results in less ozone transport from midlatitudes into the polar region and thus a negative polar TCO response. Dynamical transport plays a dominant role in modulating the Antarctic TCO after MJO P8. The magnitude of transient changes due to chemical processes is relatively weak than that caused by dynamical transport.
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