Deep Convection as the Key to the Transition From Eocene to Modern Antarctic Circumpolar Current

Xing, Qianjiang; Klocker, Andreas; Munday, David ORCID: https://orcid.org/0000-0003-1920-708X; Whittaker, Joanne. 2023 Deep Convection as the Key to the Transition From Eocene to Modern Antarctic Circumpolar Current. Geophysical Research Letters, 50 (24), e2023GL104847. 11, pp. 10.1029/2023GL104847

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Official URL: https://agupubs.onlinelibrary.wiley.com/doi/10.102...

Abstract/Summary

From the Eocene (∼50 million years ago) to today, Southern Ocean circulation has evolved from the existence of two ocean gyres to the dominance of the Antarctic Circumpolar Current (ACC). It has generally been thought that the opening of Southern Ocean gateways in the late Eocene, in addition to the alignment of westerly winds with these gateways or the presence of the Antarctic ice sheet, was a sufficient requirement for the transition to an ACC of similar strength to its modern equivalent. Nevertheless, models representing these changes produce a much weaker ACC. Here we show, using an eddying ocean model, that the missing ingredient in the transition to a modern ACC is deep convection around the Antarctic continent. This deep convection is caused by cold temperatures and high salinities due to sea-ice production around the Antarctic continent, leading to both the formation of Antarctic Bottom Water and a modern-strength ACC.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2023GL104847
ISSN:	0094-8276
Additional Keywords:	surface buoyancy forcing, deep convection, Eocene, ACC
Date made live:	21 Dec 2023 12:46 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/536537

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2023GL104847

ISSN:

0094-8276

Additional Keywords:

surface buoyancy forcing, deep convection, Eocene, ACC

Date made live:

21 Dec 2023 12:46 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/536537