Turney, CSM and Fogwill, CJ and Palmer, JG and van Sebille, E and Thomas, Z and McGlone, M and Richardson, S and Wilmshurst, JM and Fenwick, P and Zunz, V and Goosse, H and Wilson, K and Carter, L and Lipson, M and Jones, RT and Harsch, M and Clark, G and Marzinelli, E and Rogers, T and Rainsley, E and Ciasto, L and Waterman, S and Thomas, ER and Visbeck, M (2017) Tropical forcing of increased Southern Ocean climate variability revealed by a 140-year subantarctic temperate reconstruction. Climate of the Past Discussions, 13. pp. 231-248. ISSN 1814-9359

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Occupying about 14 % of the world's surface, the Southern Ocean plays a fundamental role in ocean and atmosphere circulation, carbon cycling and Antarctic ice-sheet dynamics. Unfortunately, high interannual variability and a dearth of instrumental observations before the 1950s limits our understanding of how marine–atmosphere–ice domains interact on multi-decadal timescales and the impact of anthropogenic forcing. Here we integrate climate-sensitive tree growth with ocean and atmospheric observations on southwest Pacific subantarctic islands that lie at the boundary of polar and subtropical climates (52–54° S). Our annually resolved temperature reconstruction captures regional change since the 1870s and demonstrates a significant increase in variability from the 1940s, a phenomenon predating the observational record. Climate reanalysis and modelling show a parallel change in tropical Pacific sea surface temperatures that generate an atmospheric Rossby wave train which propagates across a large part of the Southern Hemisphere during the austral spring and summer. Our results suggest that modern observed high interannual variability was established across the mid-twentieth century, and that the influence of contemporary equatorial Pacific temperatures may now be a permanent feature across the mid- to high latitudes.

Item Type: Article
Additional Information: This is the final published version of the article (version of record). It first appeared online via Copernicus GmbH at https://doi.org/10.5194/cp-13-231-2017 - please refer to any applicable terms of use of the publisher.
Subjects: G Geography. Anthropology. Recreation > GB Physical geography
Divisions: Faculty of Natural Sciences > School of Geography, Geology and the Environment
Related URLs:
Depositing User: Symplectic
Date Deposited: 21 Sep 2017 15:07
Last Modified: 25 Sep 2017 10:27
URI: http://eprints.keele.ac.uk/id/eprint/4037

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