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Evolution of the Southern Annular Mode during the past millennium
Citation
Abram, NJ and Mulvaney, R and Vimeux, F and Phipps, SJ and Turner, J and England, MH, Evolution of the Southern Annular Mode during the past millennium, Nature Climate Change, 4 pp. 564-569. ISSN 1758-678X (2014) [Refereed Article]
Copyright Statement
Copyright 2014 Macmillan Publishers Limited.
Abstract
The Southern Annular Mode (SAM) is the primary pattern of
climate variability in the Southern Hemisphere, influencing
latitudinal rainfall distribution and temperatures from the
subtropics to Antarctica. The positive summer trend in the
SAM over recent decades is widely attributed to stratospheric
ozone depletion; however, the brevity of observational records
from Antarctica—one of the core zones that defines SAM
variability—limits our understanding of long-term SAM behaviour.
Here we reconstruct annual mean changes in the SAM
since AD 1000 using, for the first time, proxy records that
encompass the full mid-latitude to polar domain across the
Drake Passage sector. We find that the SAM has undergone a
progressive shift towards its positive phase since the fifteenth
century, causing cooling of the main Antarctic continent at
the same time that the Antarctic Peninsula has warmed. The
positive trend in the SAM since AD 1940 is reproduced by
multimodel climate simulations forced with rising greenhouse
gas levels and later ozone depletion, and the long-term average
SAM index is now at its highest level for at least the past 1,000
years. Reconstructed SAM trends before the twentieth century
are more prominent than those in radiative-forcing climate
experiments and may be associated with a teleconnected
response to tropical Pacific climate. Our findings imply that
predictions of further greenhouse-driven increases in the SAM
over the coming century also need to account for the possibility
of opposing effects from tropical Pacific climate changes.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | palaeoclimate, Southern Annular Mode, Southern Hemisphere, Drake Passage, Antarctic Peninsula, greenhouse gases, ozone, tropical Pacific |
Research Division: | Earth Sciences |
Research Group: | Physical geography and environmental geoscience |
Research Field: | Palaeoclimatology |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Understanding climate change |
Objective Field: | Climate variability (excl. social impacts) |
UTAS Author: | Phipps, SJ (Dr Steven Phipps) |
ID Code: | 104734 |
Year Published: | 2014 |
Web of Science® Times Cited: | 172 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2015-11-18 |
Last Modified: | 2017-10-30 |
Downloads: | 0 |
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