Seasonal tropical cyclone predictions using optimized combinations of ENSO regions: Application to the coral sea basin

Ramsay, HA; Richman, MB; Leslie, LM

Seasonal tropical cyclone predictions using optimized combinations of ENSO regions: Application to the coral sea basin

Ramsay, HA Richman, MB Leslie, LM

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Publication Type:: Journal Article
Citation:: Journal of Climate, 2014, 27 (22), pp. 8527 - 8542
Issue Date:: 2014-01-01

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Field	Value	Language
dc.contributor.author	Ramsay, HA	en_US
dc.contributor.author	Richman, MB	en_US
dc.contributor.author	Leslie, LM https://orcid.org/0000-0001-5616-2330	en_US
dc.date.issued	2014-01-01	en_US
dc.identifier.citation	Journal of Climate, 2014, 27 (22), pp. 8527 - 8542	en_US
dc.identifier.issn	0894-8755	en_US
dc.identifier.uri	http://hdl.handle.net/10453/119028
dc.description.abstract	© 2014 American Meteorological Society. This study examines combining ENSO sea surface temperature (SST) regions for seasonal prediction of Coral Sea tropical cyclone (TC) frequency. The Coral Sea averages ~4 TCs per season, but is characterized by strong interannual variability, with 1-9 TCs per season, over the period 1977-2012. A wavelet analysis confirms that ENSO is a key contributor to Coral Sea TC count (TCC) variability. Motivated by the impact of El Niño Modoki on regional climate anomalies, a suite of 38 linear models is constructed and assessed on its ability to predict Coral Sea seasonal TCC. Seasonal predictions of TCC are generated by a leave-one-out cross validation (LOOCV). An important finding is that models made up of multiple tropical Pacific SST regions, such as those that comprise the El Niño Modoki Index (EMI) or the Trans-Niño Index (TNI), perform considerably better than models comprising only single regions, such as Niño-3.4 or Niño-4. Moreover, enhanced (suppressed) TC activity is expected in the Coral Sea when the central Pacific is anomalously cool (warm) and the eastern and western Pacific are anomalously warm (cool) during austral winter. The best crossvalidated model has persistent and statistically significantly high correlations with TCC (r > 0.5) at lead times of ~6 months prior to the mean onset of the Coral Sea TC season, whereas correlations based heavily on the widely used Niño-3.4 region are not statistically significant or meaningful (r = 0.09) for the same lead times. Of the 38 models assessed, several optimized forms of the EMI and of the TNI perform best.	en_US
dc.relation.ispartof	Journal of Climate	en_US
dc.relation.isbasedon	10.1175/JCLI-D-14-00017.1	en_US
dc.subject.classification	Meteorology & Atmospheric Sciences	en_US
dc.title	Seasonal tropical cyclone predictions using optimized combinations of ENSO regions: Application to the coral sea basin	en_US
dc.type	Journal Article
utslib.citation.volume	22	en_US
utslib.citation.volume	27	en_US
utslib.for	0909 Geomatic Engineering	en_US
utslib.for	0401 Atmospheric Sciences	en_US
utslib.for	0405 Oceanography	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	closed_access
pubs.issue	22	en_US
pubs.publication-status	Published	en_US
pubs.volume	27	en_US

Abstract:

© 2014 American Meteorological Society. This study examines combining ENSO sea surface temperature (SST) regions for seasonal prediction of Coral Sea tropical cyclone (TC) frequency. The Coral Sea averages ~4 TCs per season, but is characterized by strong interannual variability, with 1-9 TCs per season, over the period 1977-2012. A wavelet analysis confirms that ENSO is a key contributor to Coral Sea TC count (TCC) variability. Motivated by the impact of El Niño Modoki on regional climate anomalies, a suite of 38 linear models is constructed and assessed on its ability to predict Coral Sea seasonal TCC. Seasonal predictions of TCC are generated by a leave-one-out cross validation (LOOCV). An important finding is that models made up of multiple tropical Pacific SST regions, such as those that comprise the El Niño Modoki Index (EMI) or the Trans-Niño Index (TNI), perform considerably better than models comprising only single regions, such as Niño-3.4 or Niño-4. Moreover, enhanced (suppressed) TC activity is expected in the Coral Sea when the central Pacific is anomalously cool (warm) and the eastern and western Pacific are anomalously warm (cool) during austral winter. The best crossvalidated model has persistent and statistically significantly high correlations with TCC (r > 0.5) at lead times of ~6 months prior to the mean onset of the Coral Sea TC season, whereas correlations based heavily on the widely used Niño-3.4 region are not statistically significant or meaningful (r = 0.09) for the same lead times. Of the 38 models assessed, several optimized forms of the EMI and of the TNI perform best.

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http://hdl.handle.net/10453/119028