Characterizing the zonally asymmetric component of the SH circulation
Much research concerning the Southern Hemisphere(SH) zonally asymmetric circulation has focused onthe Pacific-South American mode (PSA) or the major zonalwaves. However, these large-scale decompositions maymask important local variability. In this paper the monthto-month variability explained by the...
| Published in: | Climate Dynamics |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Springer
2009
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| Subjects: | |
| Online Access: | https://doi.org/10.1007/s00382-009-0663-z http://ecite.utas.edu.au/81122 |
| Summary: | Much research concerning the Southern Hemisphere(SH) zonally asymmetric circulation has focused onthe Pacific-South American mode (PSA) or the major zonalwaves. However, these large-scale decompositions maymask important local variability. In this paper the monthto-month variability explained by the zonal waves 1 and 3 isexamined, and an alternative representation of the SH circulationis presented based on two quasi-stationary anticyclonesin the sub-Antarctic western hemisphere. Theseanticyclones are related to the zonal waves, but features oftheir variability are masked by the zonal wave decomposition;in particular, the anticyclones strengths are not positivelycovariant. They are also compared with the leadingPrincipal Components of the SH atmosphere. We show thatthey capture variance independent of the Southern AnnularMode. Additionally, they explain a generally greater fractionof the variability than the PSA, and in a manner that alsoincludes information regarding spatial variability. Theseresults have implications for analysis of the atmosphericforcingof western Antarctic climate. |
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