A Journey on the Stratospheric Highway: From Tropical Wind to Polar Spring

The Quasi-Biennial Oscillation (QBO) is the dominant mode of variability in the tropical stratosphere on interannual time scales. It not only impacts stratospheric dynamics but also plays an important role in inducing anomalous trace gas distributions. A physical connection has been found between anomalous winter subtropical mid-stratospheric nitrous oxide (N₂O) and the winter/spring Antarctic polar lower stratospheric vortex N₂O one year later in Aura's Microwave Limb Sounder (MLS) measurements. We use the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) and the Global Modeling Initiative (GMI) Chemical-Transport Model (CTM) to show the mechanism by which the QBO induces a secondary meridional circulation impacting trace gases concentrations, which are subsequently transported by the Brewer-Dobson Circulation to the polar lower stratospheric vortex over this one-year time scale. The isolation of air within the Antarctic polar vortex maintains the trace gas anomaly to a remarkable degree in contrast to the Arctic's more disturbed vortex. We will show the relationship in GEOSCCM between the polar vortex N₂O anomaly and other more chemically important constituents like inorganic chlorine (Cly) and their impact on ozone variability.