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The effects of joint ENSO–Antarctic Oscillation forcing on the McMurdo Dry Valleys, Antarctica

Published online by Cambridge University Press:  14 November 2006

N.A.N. Bertler
Affiliation:
Antarctic Research Centre, Victoria University, PO Box 600, Wellington, New Zealand GNS Science, 1 Fairway Drive, Avalon, Lower Hutt 5010, New Zealand Climate Change Institute, University of Maine, Orono, ME 04469, USA
T.R. Naish
Affiliation:
Antarctic Research Centre, Victoria University, PO Box 600, Wellington, New Zealand GNS Science, 1 Fairway Drive, Avalon, Lower Hutt 5010, New Zealand
H. Oerter
Affiliation:
Alfred Wegener Institute, Postfach 120161, 27515 Bremerhaven, Germany
S. Kipfstuhl
Affiliation:
Alfred Wegener Institute, Postfach 120161, 27515 Bremerhaven, Germany
P.J. Barrett
Affiliation:
Antarctic Research Centre, Victoria University, PO Box 600, Wellington, New Zealand
P.A. Mayewski
Affiliation:
Climate Change Institute, University of Maine, Orono, ME 04469, USA
K. Kreutz
Affiliation:
Climate Change Institute, University of Maine, Orono, ME 04469, USA

Abstract

Stable oxygen analyses and snow accumulation rates from snow pits sampled in the McMurdo Dry Valleys have been used to reconstruct variations in summer temperature and moisture availability over the last four decades. The temperature data show a common interannual variability, with strong regional warmings occurring especially in 1984/85, 1995/96 and 1990/91 and profound coolings during 1977/78, 1983/84, 1988/89, 1993/94, and 1996/97. Annual snow accumulation shows a larger variance between sites, but the early 1970s, 1984, 1997, and to a lesser degree 1990/91 are characterized overall by wetter conditions, while the early and late 1980s show low snow accumulation values. Comparison of the reconstructed and measured summer temperatures with the Southern Oscillation Index (SOI) and the Antarctic Oscillation (AAO) yield statistically significant correlations, which improve when phase-relationships are considered. A distinct change in the phase relationship of the correlation is observed, with the SOI-AAO leading over the temperature records by one year before, and lagging by one year after 1988. These results suggest that over the last two decades summer temperatures are influenced by opposing El Niño Southern Oscillation and AAO forcings and support previous studies that identified a change in the Tropical-Antarctic teleconnection between the 1980s and 1990s.

Type
Research Article
Copyright
Antarctic Science Ltd 2006

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