- Title
- Impact of different ENSO regimes on southwest pacific tropical cyclones
- Creator
- Chand, Savin; McBride, John; Tory, Kevin; Wheeler, Matthew; Walsh, Kevin
- Date
- 2013
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/101913
- Identifier
- vital:10705
- Identifier
- ISBN:0894-8755
- Abstract
- The influence of different types of ENSO on tropical cyclone (TC) interannual variability in the central southwest Pacific region (58-258S, 1708E-1708W) is investigated. Using empirical orthogonal function analysis and an agglomerative hierarchical clustering of early tropical cyclone season Pacific sea surface temperature, years are classified into four separate regimes (i.e., canonical El Niño, canonical La Niña, positive-neutral, and negative-neutral) for the period between 1970 and 2009.These regimes are found to have a large impact on TC genesis over the central southwest Pacific region. Both the canonical El Niño and the positive-neutral years have increased numbers of cyclones, with an average of 4.3 yr-1 for positive-neutral and 4 yr-1 for canonical El Niño. In contrast, during a La Niña and negative-neutral events, substantially fewer TCs (averages of ;2.2 and 2.4 yr-1, respectively) are observed in the central southwest Pacific. The enhancement of TC numbers in both canonical El Niño and positive-neutral years is associated with the extension of favorable low-level cyclonic relative vorticity, and low vertical wind shear eastward across the date line. Relative humidity and SST are also very conducive forgenesis in this region during canonical El Niño and positiveneutral events. The patterns are quite different, however, with the favorable conditions concentrated in the date line region for the positive-neutral, as compared with conditions farther eastward for the canonical El Niño regime. A significant result of the study is the demonstration that ENSO-neutralevents can be objectively clustered into two separate regimes, each with very different impacts on TCgenesis. © 2013 American Meteorological Society.
- Relation
- Journal of Climate Vol. 26, no. 2 (2013), p. 600-608
- Rights
- Copyright AMS
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- Agglomerative hierarchical clustering; Cyclonic relative vorticity; Empirical orthogonal function analysis; Favorable conditions; Interannual variability; Sea surface temperature (SST); Tropical cyclone; Vertical wind shear; Atmospheric temperature; Hurricanes; Multi agent systems; Separation; Nickel compounds; Cyclogenesis; Ecological impact; El Nino; El Nino-Southern Oscillation; La Nina; Relative humidity; Sea surface temperature; Vorticity; Wind shear; Pacific Ocean; Pacific Ocean (Southwest); 0401 Atmospheric Sciences; 0405 Oceanography
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