Deepening of Southern Ocean gateway leads to abrupt onset of a deep-reaching meridional overturning circulation

Xing, Q.B.; Klocker, A.; Munday, D. ORCID:; Whittaker, J.M.. 2023 Deepening of Southern Ocean gateway leads to abrupt onset of a deep-reaching meridional overturning circulation. Geophysical Research Letters, 50 (19), e2023GL104382. 10, pp.

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© 2023. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Geophysical Research Letters - 2023 - Xing - Deepening of Southern Ocean Gateway Leads to Abrupt Onset of a Deep‐Reaching.pdf - Published Version
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During the Eocene and the Eocene-Oligocene transition, the lower cell of the meridional overturning circulation (MOC), associated with bottom water formation, underwent changes associated with the geological evolution of Southern Ocean gateways. These are important for the Cenozoic climate transition from Greenhouse to Icehouse, but their dynamics still remain elusive. We demonstrate, using an idealized eddying ocean model, that the opening of a gateway leads to the abrupt onset of a vigorous, deep-reaching, MOC. This MOC has a maximum transport for a shallow gateway, and decreases with further deepening of the gateway. This abrupt change in the MOC can be explained through the ability with which standing meanders—turbulent features located downstream of the gateway—can induce deep vertical heat transport at high latitudes where bottom waters are produced. Our results demonstrate the crucial role of turbulent processes in setting the strength of the global ocean's deep-reaching MOC.

Item Type: Publication - Article
Digital Object Identifier (DOI):
ISSN: 0094-8276
Date made live: 09 Oct 2023 16:21 +0 (UTC)

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