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Much research concerning the Southern Hemisphere (SH) zonally asymmetric circulation has focused on the Pacific-South American mode (PSA) or the major zonal waves. However, these large-scale decompositions may mask important local variability. In this paper the monthto- month variability explained by the zonal waves 1 and 3 is examined, and an alternative representation of the SH circulation is presented based on two quasi-stationary anticyclones in the sub-Antarctic western hemisphere. These anticyclones are related to the zonal waves, but features of their variability are masked by the zonal wave decomposition; in particular, the anticyclones’ strengths are not positively covariant. They are also compared with the leading Principal Components of the SH atmosphere. We show that they capture variance independent of the Southern Annular Mode. Additionally, they explain a generally greater fraction of the variability than the PSA, and in a manner that also includes information regarding spatial variability. These results have implications for analysis of the atmosphericforcing of western Antarctic climate.

Item Type:	Refereed Article
Keywords:	climate variability, Southern Hemisphere, zonal waves, Pacific-South American Mode, Southern Annular Mode
Research Division:	Earth Sciences
Research Group:	Atmospheric sciences
Research Field:	Atmospheric dynamics
Objective Division:	Environmental Policy, Climate Change and Natural Hazards
Objective Group:	Understanding climate change
Objective Field:	Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:	Hobbs, WR (Dr Will Hobbs)
ID Code:	81122
Year Published:	2009
Web of Science® Times Cited:	18
Deposited By:	IMAS Research and Education Centre
Deposited On:	2012-11-22
Last Modified:	2012-11-28
Downloads:	323 View Download Statistics