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Analysing the timing of peak warming and minimum winter sea-ice extent in the Southern Ocean during MIS 5e

Analysing the timing of peak warming and minimum winter sea-ice extent in the Southern Ocean during MIS 5e
Analysing the timing of peak warming and minimum winter sea-ice extent in the Southern Ocean during MIS 5e
The peak of the Last Interglacial, Marine Isotope Stage (MIS) 5e (130–116 ka), provides a valuable ‘process analogue’ for validating the climatic feedbacks and forcings likely active under future anthropogenic warming. Reconstructing exact timings of MIS 5e peak warming and minimum winter sea-ice extent (WSIE) throughout the Southern Ocean (SO) will help to identify the interactions and feedbacks within the ice-ocean system. Here we present a new MIS 5e marine sediment record from the SW Atlantic sector together with 28 published core records (chronologies standardised to the LR04 δ18O benthic stack; Lisiecki and Raymo, 2005) to investigate the timing and sequence of minimum WSIE and peak warming across the SO. Sea-surface temperatures (SSTs) peaked earliest in the Indian (20oE–150oE) and Atlantic (70oW–20oE) sectors, at 128.7 ± 0.8 ka and 127.4 ± 1.1 ka respectively, followed by the Pacific sector (150oE–70oW) at 124.9 ± 3.6 ka. The interval of minimum WSIE for all three sectors occurred within the period from 129–125 ka, consistent with the ∼128 ka sea salt flux minimum in Antarctic ice cores. Minimum WSIE appears to have coincided with peak July insolation at 55 oS, suggesting it could be linked with the mildest winters. The reduced WSIE during MIS 5e would have likely reduced the production of deep- and bottom water masses, inhibiting storage of CO2 in the abyssal ocean and lowering nutrient availability in SO surface waters. Examining a wide spatial range of proxy records for MIS 5e is a critical step forward in understanding climatic interactions and processes that will be active under warmer global temperatures.
Interglacial, Palaeoceanography, Sediment cores, Southern Ocean
0277-3791
Chadwick, M.
aaf95186-1d37-4866-8899-13abb9b7257a
Allen, C.s.
473d2ef9-c051-4141-8c81-a593d9f84a1e
Sime, L.c.
27e4dd9a-2b54-4f4c-b345-31fff4a2f2b6
Hillenbrand, C.-d.
0d081424-9401-4395-9776-efa93f806bba
Chadwick, M.
aaf95186-1d37-4866-8899-13abb9b7257a
Allen, C.s.
473d2ef9-c051-4141-8c81-a593d9f84a1e
Sime, L.c.
27e4dd9a-2b54-4f4c-b345-31fff4a2f2b6
Hillenbrand, C.-d.
0d081424-9401-4395-9776-efa93f806bba

Chadwick, M., Allen, C.s., Sime, L.c. and Hillenbrand, C.-d. (2020) Analysing the timing of peak warming and minimum winter sea-ice extent in the Southern Ocean during MIS 5e. Quaternary Science Reviews, 229, [106134]. (doi:10.1016/j.quascirev.2019.106134).

Record type: Article

Abstract

The peak of the Last Interglacial, Marine Isotope Stage (MIS) 5e (130–116 ka), provides a valuable ‘process analogue’ for validating the climatic feedbacks and forcings likely active under future anthropogenic warming. Reconstructing exact timings of MIS 5e peak warming and minimum winter sea-ice extent (WSIE) throughout the Southern Ocean (SO) will help to identify the interactions and feedbacks within the ice-ocean system. Here we present a new MIS 5e marine sediment record from the SW Atlantic sector together with 28 published core records (chronologies standardised to the LR04 δ18O benthic stack; Lisiecki and Raymo, 2005) to investigate the timing and sequence of minimum WSIE and peak warming across the SO. Sea-surface temperatures (SSTs) peaked earliest in the Indian (20oE–150oE) and Atlantic (70oW–20oE) sectors, at 128.7 ± 0.8 ka and 127.4 ± 1.1 ka respectively, followed by the Pacific sector (150oE–70oW) at 124.9 ± 3.6 ka. The interval of minimum WSIE for all three sectors occurred within the period from 129–125 ka, consistent with the ∼128 ka sea salt flux minimum in Antarctic ice cores. Minimum WSIE appears to have coincided with peak July insolation at 55 oS, suggesting it could be linked with the mildest winters. The reduced WSIE during MIS 5e would have likely reduced the production of deep- and bottom water masses, inhibiting storage of CO2 in the abyssal ocean and lowering nutrient availability in SO surface waters. Examining a wide spatial range of proxy records for MIS 5e is a critical step forward in understanding climatic interactions and processes that will be active under warmer global temperatures.

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Chadwick_Manuscript_revised - Accepted Manuscript
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Accepted/In Press date: 8 December 2019
e-pub ahead of print date: 20 December 2019
Published date: 1 February 2020
Keywords: Interglacial, Palaeoceanography, Sediment cores, Southern Ocean

Identifiers

Local EPrints ID: 440895
URI: http://eprints.soton.ac.uk/id/eprint/440895
ISSN: 0277-3791
PURE UUID: 5dd02402-517c-4de7-893b-05e72d108ff7

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Date deposited: 21 May 2020 16:33
Last modified: 22 Nov 2021 08:08

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Contributors

Author: M. Chadwick
Author: C.s. Allen
Author: L.c. Sime
Author: C.-d. Hillenbrand

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