The role of eddies in the Southern Ocean temperature response to the southern annular mode

Screen, JA, Gillet, NP, Stevens, DP, Marshall, GJ and Roscoe, HK (2009) The role of eddies in the Southern Ocean temperature response to the southern annular mode. Journal of Climate, 22 (3). pp. 806-818.

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    Abstract

    The role of eddies in modulating the Southern Ocean response to the southern annular mode (SAM) is examined, using an ocean model run at multiple resolutions from coarse to eddy resolving. The high-resolution versions of the model show an increase in eddy kinetic energy that peaks 2-3 yr after a positive anomaly in the SAM index. Previous work has shown that the instantaneous temperature response to the SAM is characterized by predominant cooling south of 45°S and warming to the north. At all resolutions the model captures this temperature response. This response is also evident in the coarse-resolution implementation of the model with no eddy mixing parameterization, showing that eddies do not play an important role in the instantaneous response. On the longer time scales, an intensification of the mesoscale eddy field occurs, which causes enhanced poleward heat flux and drives warming south of the oceanic Polar Front. This warming is of greater magnitude and occurs for a longer period than the initial cooling response. The results demonstrate that this warming is surface intensified and strongest in the mixed layer. Non-eddy-resolving models are unable to capture the delayed eddy-driven temperature response to the SAM. The authors therefore question the ability of coarse-resolution models, such as those commonly used in climate simulations, to accurately represent the full impacts of the SAM on the Southern Ocean.

    Item Type: Article
    Faculty \ School: Faculty of Science > School of Mathematics
    Related URLs:
    Depositing User: Rosie Cullington
    Date Deposited: 23 Feb 2011 11:34
    Last Modified: 01 Nov 2018 10:31
    URI: https://ueaeprints.uea.ac.uk/id/eprint/24483
    DOI: 10.1175/2008JCLI2416.1

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