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The years of El Nino, La Nina and interactions with the tropical Indian Ocean


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Meyers, G, McIntosh, PC, Pigot, L and Pook, MJ 2007 , 'The years of El Nino, La Nina and interactions with the tropical Indian Ocean' , Journal of Climate, vol. 20, no. 1 , pp. 2872-2880 , doi: 10.1175/JCLI4152.1.

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The Indian Ocean zonal dipole is a mode of variability in sea surface temperature that seriously affects
the climate of many nations around the Indian Ocean rim, as well as the global climate system. It has been
the subject of increasing research, and sometimes of scientific debate concerning its existence/nonexistence
and dependence/independence on/from the El Niño–Southern Oscillation, since it was first clearly identified
in Nature in 1999. Much of the debate occurred because people did not agree on what years are the El Niño
or La Niña years, not to mention the newly defined years of the positive or negative dipole. A method that
identifies when the positive or negative extrema of the El Niño–Southern Oscillation and Indian Ocean
dipole occur is proposed, and this method is used to classify each year from 1876 to 1999. The method is
statistical in nature, but has a strong basis on the oceanic physical mechanisms that control the variability
of the near-equatorial Indo-Pacific basin. Early in the study it was found that some years could not be
clearly classified due to strong decadal variation; these years also must be recognized, along with the reason
for their ambiguity. The sensitivity of the classification of years is tested by calculating composite maps of
the Indo-Pacific sea surface temperature anomaly and the probability of below median Australian rainfall
for different categories of the El Niño–Indian Ocean relationship.

Item Type: Article
Authors/Creators:Meyers, G and McIntosh, PC and Pigot, L and Pook, MJ
Journal or Publication Title: Journal of Climate
Publisher: American Meteorological Society
ISSN: 0894-8755
DOI / ID Number: 10.1175/JCLI4152.1
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