Does the Southern Annular Mode contribute to the persistence of the multidecade-long drought over southwest Western Australia?
Article
Article Title | Does the Southern Annular Mode contribute to the persistence of the multidecade-long drought over southwest Western Australia? |
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ERA Journal ID | 1874 |
Article Category | Article |
Authors | Cai, W., van Rensch, P., Borlace, S. and Cowan, T. |
Journal Title | Geophysical Research Letters |
Journal Citation | 38 (14) |
Number of Pages | 5 |
Year | 2011 |
Publisher | John Wiley & Sons |
ISSN | 0094-8276 |
1944-8007 | |
Digital Object Identifier (DOI) | https://doi.org/10.1029/2011GL047943 |
Web Address (URL) | https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL047943 |
Abstract | [1] Record low austral winter rainfall totals over southwest Western Australia (SWWA) in 2010 saw a continuation of the multidecade-long winter drought plaguing the region. During this season, the highest recorded positive Southern Annular Mode (SAM) value was measured, adding weight to an association of a positive SAM with anomalously low SWWA winter rainfall (SWR), and vice-versa. However, such a SAM-SWR teleconnection has been recently questioned. Using observational data in the post-1979 satellite era, it is shown that such a SAM influence does exist. This coherence is confirmed with 1150 years of modelled 20th century SWR anomalies and SAM values from 23 climate models, showing that a nonlinear impact operates: the influence from a negative SAM is greater than that from a positive SAM. This explains why a small positive shift in the SAM can cause a large SWR reduction, as has been observed. A further test shows that models with a greater positive SAM trend systematically produce a greater future SWR reduction. As all climate models project an increase in the SAM these results suggest that as global warming continues unabated, SWWA winter droughts will be more persistent as atmospheric conditions become more unfavourable for drought-breaking rains. |
ANZSRC Field of Research 2020 | 370105. Atmospheric dynamics |
370201. Climate change processes | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia |
https://research.usq.edu.au/item/z09ww/does-the-southern-annular-mode-contribute-to-the-persistence-of-the-multidecade-long-drought-over-southwest-western-australia
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