Southern Annular Mode-like changes in southwestern Patagonia at centennial timescales over the last three millennia

Late twentieth-century instrumental records reveal a persistent southward shift of the Southern Westerly Winds during austral summer and autumn associated with a positive trend of the Southern Annular Mode (SAM) and contemporaneous with glacial recession, steady increases in atmospheric temperatures...

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Veröffentlicht in:Nature communications 2014-07, Vol.5 (1), p.4375-4375, Article 4375
Hauptverfasser: Moreno, Patricio I., Vilanova, I., Villa-Martínez, R., Garreaud, R. D., Rojas, M., De Pol-Holz, R.
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Sprache:eng
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Zusammenfassung:Late twentieth-century instrumental records reveal a persistent southward shift of the Southern Westerly Winds during austral summer and autumn associated with a positive trend of the Southern Annular Mode (SAM) and contemporaneous with glacial recession, steady increases in atmospheric temperatures and CO 2 concentrations at a global scale. However, despite the clear importance of the SAM in the modern/future climate, very little is known regarding its behaviour during pre-Industrial times. Here we present a stratigraphic record from Lago Cipreses (51°S), southwestern Patagonia, that reveals recurrent ~200-year long dry/warm phases over the last three millennia, which we interpret as positive SAM-like states. These correspond in timing with the Industrial revolution, the Mediaeval Climate Anomaly, the Roman and Late Bronze Age Warm Periods and alternate with cold/wet multi-centennial phases in European palaeoclimate records. We conclude that SAM-like changes at centennial timescales in southwestern Patagonia represent in-phase interhemispheric coupling of palaeoclimate over the last 3,000 years through atmospheric teleconnections. The Southern Annular Mode (SAM) strongly impacts modern Southern Hemisphere climate, yet insight into its pre-industrial behaviour is lacking. Here, the authors present a high-resolution lake record and show that SAM variability coincided with major centennial-scale climate changes over the past 3,000 years.
ISSN:2041-1723
2041-1723
DOI:10.1038/ncomms5375