Antarctic Science


Special Issue: The Latitudinal Gradient Project (LGP)

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


N.A.N. Bertler a1a2a4c1, T.R. Naish a2a1, H. Oerter a3, S. Kipfstuhl a3, P.J. Barrett a1, P.A. Mayewski a4 and K. Kreutz a4
a1 Antarctic Research Centre, Victoria University, PO Box 600, Wellington, New Zealand
a2 GNS Science, 1 Fairway Drive, Avalon, Lower Hutt 5010, New Zealand
a3 Alfred Wegener Institute, Postfach 120161, 27515 Bremerhaven, Germany
a4 Climate Change Institute, University of Maine, Orono, ME 04469, USA

Article author query
bertler nan   [PubMed][Google Scholar] 
naish tr   [PubMed][Google Scholar] 
oerter h   [PubMed][Google Scholar] 
kipfstuhl s   [PubMed][Google Scholar] 
barrett pj   [PubMed][Google Scholar] 
mayewski pa   [PubMed][Google Scholar] 
kreutz k   [PubMed][Google Scholar] 

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.

(Published Online November 14 2006)
(Received January 3 2006)
(Accepted September 7 2006)


Key Words: Amundsen Sea Low; climate drivers; Latitudinal Gradient Project; snow analysis; Southern Oscillation Index; water isotopes.

Correspondence:
c1 nancy.bertler@vuw.ac.nz


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