The role of vertical eddy flux in Southern Ocean heat uptake

A. K. Morrison*, O. A. Saenko, A. Mc C. Hogg, P. Spence

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    53 Citations (Scopus)

    Abstract

    The role of changing vertical eddy heat flux on Southern Ocean heat uptake is investigated in an idealized eddy-permitting ocean model. Enhanced air-sea heat flux drives deep-reaching southern warming, due to a reduction in the isopycnal meridional temperature gradient and therefore decreased upward eddy heat flux. This mechanism is qualitatively similar in models with either permitted or parameterized eddies, due to its dependence on the isopycnal temperature gradient rather than the dynamical response of the eddy field. In contrast, increased wind stress drives mid-depth Southern Ocean cooling through an enhancement of the eddy field and resultant eddy heat divergence. The transient cooling extends over multiple decades while the mean flow adjusts to balance the faster eddy response. This wind-driven cooling mechanism has not been captured by coarse resolution models with fixed eddy parameterizations and is a possible candidate for the recent cooling observed in the Southern Ocean. Key Points Southern Ocean warming occurs via enhanced isopycnal temperature gradient Parameterised eddies are sufficient to model this change Enhanced wind stress drives transient cooling due to fast eddy response

    Original languageEnglish
    Pages (from-to)5445-5450
    Number of pages6
    JournalGeophysical Research Letters
    Volume40
    Issue number20
    DOIs
    Publication statusPublished - 28 Oct 2013

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