Orme, Lisa and Crosta, Xavier and Miettinen, Arto and Divine, Dmitry and Husum, Katrine and Isaksson, Elisabeth and Wacker, Lucas and Mohan, Rahul and Ther, Olivier and Ikehara, Minoru (2020) Sea surface temperature in the Indian sector of the Southern Ocean over the Late Glacial and Holocene. Climate of the Past, 16. pp. 1451-1467. ISSN 1814-9332

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Abstract

Centennial- and millennial-scale variability ofSouthern Ocean temperature over the Holocene is poorlyknown, due to both short instrumental records and sparselydistributed high-resolution temperature reconstructions, withevidence for past temperature variations in the region com-ing mainly from ice core records. Here we present a high-resolution (∼60 year), diatom-based sea surface tempera-ture (SST) reconstruction from the western Indian sector ofthe Southern Ocean that spans the interval 14.2 to 1.0 ka (cal-ibrated kiloyears before present). During the late deglacia-tion, the new SST record shows cool temperatures at 14.2–12.9 ka and gradual warming between 12.9 and 11.6 ka inphase with atmospheric temperature evolution. This supportsthe evolution of the Southern Ocean SST during the deglacia-tion being linked with a complex combination of processesand drivers associated with reorganisations of atmosphericand oceanic circulation patterns. Specifically, we suggest thatSouthern Ocean surface warming coincided, within the dat-ing uncertainties, with the reconstructed slowdown of theAtlantic Meridional Overturning Circulation (AMOC), ris-ing atmospheric CO2levels, changes in the southern west-erly winds and enhanced upwelling. During the Holocenethe record shows warm and stable temperatures from 11.6to 8.7 ka followed by a slight cooling and greater variabilityfrom 8.7 to 1 ka, with a quasi-periodic variability of 200–260 years identified by spectral analysis. We suggest that the increased variability during the mid- to late Holocene reflectsthe establishment of centennial variability in SST connectedwith changes in the high-latitude atmospheric circulation andSouthern Ocean convection.

Item Type:	Article
Keywords:	Sea surface temperature; Indian sector; Southern Ocean; Late Glacial; Holocene;
Academic Unit:	Faculty of Social Sciences > Geography Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	13936
Identification Number:	https://doi.org/10.5194/cp-16-1451-2020
Depositing User:	Lisa Orme
Date Deposited:	04 Feb 2021 12:41
Journal or Publication Title:	Climate of the Past
Publisher:	European Geosciences Union (EGU)
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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