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

QUATERNARY SCIENCE REVIEWS

卷:229

Article

Chadwick, M.^1,2  Allen, C. S.¹  Sime, L. C.¹  Hillenbrand, C. -D.¹ 

[1] British Antarctic Survey, Madingley Rd, Cambridge CB3 0ET, England

[2] Univ Southampton, Natl Oceanog Ctr, Ocean & Earth Sci, Waterfront Campus,European Way, Southampton SO14 3ZH, Hants, England

关键词: Interglacial;    Sediment cores;    Palaeoceanography;    Southern Ocean;   

DOI  :  10.1016/j.quascirev.2019.106134

来源: Elsevier

【 摘 要 】

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 LRO4 5180 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 (20 E -150 E) and Atlantic (70 W-20 E) sectors, at 128.7 0.8 ka and 127.4 1.1 ka respectively, followed by the Pacific sector (150 E-70 W) 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 S, 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. (C) 2019 Elsevier Ltd. All rights reserved.

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