Impact of polar ozone depletion on subtropical precipitation

• Published in: Science
• Main Authors: Kang, S., Polvani, L., Fyfe, J., Sigmond, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: Antarc*; Antarctic
• Online Access: http://hdl.handle.net/21.11116/0000-000E-91B2-4; http://hdl.handle.net/21.11116/0000-000E-91B7-F

The Antarctic ozone hole has led to increased summertime precipitation in the subtropics of the Southern Hemisphere. Over the past half-century, the ozone hole has caused a poleward shift of the extratropical westerly jet in the Southern Hemisphere. Here, we argue that these extratropical circulation changes, resulting from ozone depletion, have substantially contributed to subtropical precipitation changes. Specifically, we show that precipitation in the southern subtropics in austral summer increases significantly when climate models are integrated with reduced polar ozone concentrations. Furthermore, the observed patterns of subtropical precipitation change, from 1979 to 2000, are very similar to those in our model integrations, where ozone depletion alone is prescribed. In both climate models and observations, the subtropical moistening is linked to a poleward shift of the extratropical westerly jet. Our results highlight the importance of polar regions for the subtropical hydrological cycle.