Tropical forcing of increased Southern Ocean climate variability revealed by a 140-year subantarctic temperature reconstruction
Turney, C.S.M.; Fogwill, C.J.; Palmer, J.G.; van Sebille, E.; Thomas, Z.; McGlone, M.; Richardson, S.; Wilmshurst, J.M.; Fenwick, P.; Zunz, V.; Goosse, H.; Wilson, K.-J.; Carter, L.; Lipson, M.; Jones, R.T.; Harsch, M.; Clark, G.; Marzinelli, E.; Rogers, T.; Rainsley, E.; Ciasto, L.; Waterman, S.; Thomas, E.R.; Visbeck, M. (2017). Tropical forcing of increased Southern Ocean climate variability revealed by a 140-year subantarctic temperature reconstruction. Clim. Past 13(3): 231-248. https://dx.doi.org/10.5194/cp-13-231-2017 In: Climate of the Past. Copernicus: Göttingen. ISSN 1814-9324; e-ISSN 1814-9332, more |   |
| Authors | | Top | - Turney, C.S.M.
- Fogwill, C.J.
- Palmer, J.G.
- van Sebille, E.
- Thomas, Z.
- McGlone, M.
- Richardson, S.
- Wilmshurst, J.M.
| - Fenwick, P.
- Zunz, V., more
- Goosse, H., more
- Wilson, K.-J.
- Carter, L.
- Lipson, M.
- Jones, R.T.
- Harsch, M.
| - Clark, G.
- Marzinelli, E.
- Rogers, T.
- Rainsley, E.
- Ciasto, L.
- Waterman, S.
- Thomas, E.R.
- Visbeck, M.
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| Abstract | 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. |
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