The non-linear impact of El Nino, La Nina and the Southern Oscillation on seasonal and regional Australian precipitation

Chung, Christine T. Y. and Power, Scott B. (2017) The non-linear impact of El Nino, La Nina and the Southern Oscillation on seasonal and regional Australian precipitation. Journal of Southern Hemisphere Earth Systems Science, 67 (1). pp. 25-45.

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Abstract

The relationship between El Niño-Southern Oscillation (ENSO) indices and precipitation (P) in some parts of Australia has previously been shown to be non-linear on annual and seasonal time scales. Here we examine the relationship between P and the Southern Oscillation Index (SOI) at all Australian locations and in all seasons. We show that in many Australian regions, there is more-than-expected P during strong La Niña years (SOI>13), but less-than-expected drying during strong El Niño years (SOI<-13). Statistically significant non-linearities are found over northern NT, QLD and parts of WA during SON, and parts of QLD, NSW, and VIC during DJF, when regressing P against June-December SOI. During the MAM immediately preceding a June-December ENSO year, and during JJA, the rainfall-SOI relationship is linear over most of the country. Systematic eastward shifts in P patterns can explain non-linearities over northern Australia, but do not explain non-linearities southward of approximately 20°S. The seasonal P distribution is decomposed into FP, the fraction of days on which P falls, and PD, the amount of rain per day on days when P is non-zero. Both FP and PD display a non-linear relationship with SOI similar to the P-SOI relationship, although the relative influence of each term on P is spatially and seasonally dependent.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Articles are published under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 (CC-BY-NC-ND) licence (http://creativecommons.org/licenses/by-nc-nd/4.0/deed.en_US). Under this licence, readers can share, redistribute and reuse the article without permission as long as it is not done for commercial purposes and as long as the article is not changed. Those wanting to make derivatives or use content commercially can contact us to discuss your needs. When sharing or reusing any article, attribution must be given to the original source. Alternative Creative Commons licences are available on request.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 11 Oct 2021 04:43
Last Modified: 20 Oct 2021 00:22
Uncontrolled Keywords: air-sea interaction; el Nino; La Nina
Fields of Research (2008): 04 Earth Sciences > 0401 Atmospheric Sciences > 040105 Climatology (excl.Climate Change Processes)
Fields of Research (2020): 37 EARTH SCIENCES > 3702 Climate change science > 370202 Climatology
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9603 Climate and Climate Change > 960304 Climate Variability (excl. Social Impacts)
Socio-Economic Objectives (2020): 19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1905 Understanding climate change > 190502 Climate variability (excl. social impacts)
Identification Number or DOI: doi:10.22499/3.6701.003
URI: http://eprints.usq.edu.au/id/eprint/42417

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