Direct and ozone-mediated forcing of the Southern Annular Mode by greenhouse gases

Morgenstern, Olaf, Zeng, Guang, Dean, Sam M., Joshi, Manoj, Abraham, N. Luke and Osprey, Annette (2014) Direct and ozone-mediated forcing of the Southern Annular Mode by greenhouse gases. Geophysical Research Letters, 41 (24). 9050–9057. ISSN 0094-8276

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    Abstract

    We assess the roles of long-lived greenhouse gases and ozone depletion in driving meridional surface pressure gradients in the southern extratropics; these gradients are a defining feature of the Southern Annular Mode. Stratospheric ozone depletion is thought to have caused a strengthening of this mode during summer, with increasing long-lived greenhouse gases playing a secondary role. Using a coupled atmosphere-ocean chemistry-climate model, we show that there is cancelation between the direct, radiative effect of increasing greenhouse gases by the also substantial indirect—chemical and dynamical—feedbacks that greenhouse gases have via their impact on ozone. This sensitivity of the mode to greenhouse gas-induced ozone changes suggests that a consistent implementation of ozone changes due to long-lived greenhouse gases in climate models benefits the simulation of this important aspect of Southern Hemisphere climate.

    Item Type: Article
    Uncontrolled Keywords: southern annular mode,climate change,southern hemisphere,ozone,regression,greenhouse gas
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    University of East Anglia > Faculty of Science > Research Groups > Climatic Research Unit
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    Depositing User: Pure Connector
    Date Deposited: 16 Dec 2014 13:50
    Last Modified: 25 Jul 2018 10:18
    URI: https://ueaeprints.uea.ac.uk/id/eprint/51371
    DOI: 10.1002/2014GL062140

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