The Southern Hemisphere westerlies in the Australasian sector over the last glacial cycle: a synthesis

Shulmeister, J., Goodwin, I., Renwick, J., Harle, K., Armand, L., McGlone, M. S., Cook, E., Dodson, J.,, Hesse, P. P., Mayewski, P. and Curran, M. (2004) The Southern Hemisphere westerlies in the Australasian sector over the last glacial cycle: a synthesis. Quaternary International, 118/119 Climates, human, and natural system of the PEPII transect: 23-53. doi:10.1016/S1040-6182(03)00129-0


Author Shulmeister, J.
Goodwin, I.
Renwick, J.
Harle, K.
Armand, L.
McGlone, M. S.
Cook, E.
Dodson, J.,
Hesse, P. P.
Mayewski, P.
Curran, M.
Title The Southern Hemisphere westerlies in the Australasian sector over the last glacial cycle: a synthesis
Journal name Quaternary International   Check publisher's open access policy
ISSN 1040-6182
Publication date 2004
Year available 2004
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1016/S1040-6182(03)00129-0
Volume 118/119
Issue Climates, human, and natural system of the PEPII transect
Start page 23
End page 53
Total pages 31
Editor J. R. Dodson
D.Taylor
Y. Ono
P. Wang
Place of publication Oxford ; New York
Publisher Pergamon Press
Language eng
Subject 050205 Environmental Management
Abstract The Southern Hemisphere westerlies in the southwest Pacific are known to have waxed and waned numerous times during the last two glacial cycles, though even semi-continuous histories of the westerlies extend back no more than about 20,000 years. We have good evidence for at least three scales of events. A westerly maximum occurs at the Last Glacial Maximum. There is less conclusive evidence for another westerly maximum in the late Holocene and for a minimum at ca. 11 ka. It is too early to ascribe even a cycle to these data but there are grounds to suggest that Milankovitch precessional forcing may underlie the observed pattern. There is also a quasi-2600-year cycle present in Antarctic ice cores that appears to correlate to variation in westerly flow. There is strong centennial-scale variability. In historical times, the Little Ice Age (LIA: ca. 1400-1850) was associated with a poleward shift in the circumpolar trough in the Southern Ocean, strengthened westerly circulation over Tasmania and a strengthening of southwesterly circulation and neoglaciation in southern New Zealand, while the preceding period (800-1400 AD) was less certainly marked by reduced westerly flow. From modern records we know that decadal and inter-annual variability is important (e.g. Pacific Decadal Oscillation, High Latitude Mode also known as the Antarctic Oscillation, El Nino Southern Oscillation). Only a minority of the proxies examined can identify changes on these temporal scales but data from tree-rings, ice cores and laminated lake sediments do indicate systematic changes in these phenomena through time. Rossby wave patterns are shown to play a critical role in long duration events as well as at the synoptic scale. We conclude that westerly circulation is as strong now as at any time in the last glacial cycle. In addition, changes in latitudinal boundaries in the westerlies may be nearly as large in inter-annual zonal shifts (ca. 2degrees maximum) as in glaciation-interglaciation movements (ca. 3-4degrees). There is, however, reasonable evidence of strengthening/weakening across much of the westerly belt at westerly maxima/minima such as the LIA/early Holocene. (C) 2003 Elsevier Ltd and INQUA. All rights reserved.
Keyword antarctic sea-ice
southwest pacific-ocean
franz-josef-glacier
late pleistocene vegetation
level pressure variability
late quaternary vegetation
southeastern north-island
general-circulation model
loess-paleosol sequences
eastern new-zealand
Q-Index Code C1

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: Excellence in Research Australia (ERA) - Collection
School of Geography, Planning and Environmental Management Publications
 
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