Open AccessTropical Cyclone Climatology of the South Pacific Ocean and Its Relationship to El Niño–Southern Oscillation
Author(s) -
Andrew Dowdy,
Lixin Qi,
David A. Jones,
Hamish A. Ramsay,
Robert Fawcett,
Yuriy Kuleshov
Publication year - 2012
Publication title -
journal of climate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.315
H-Index - 287
eISSN - 1520-0442
pISSN - 0894-8755
DOI - 10.1175/jcli-d-11-00647.1
Subject(s) - climatology , cyclogenesis , tropical cyclone , tropical cyclogenesis , madden–julian oscillation , geology , african easterly jet , sea surface temperature , cyclone (programming language) , tropical cyclone rainfall forecasting , wind shear , mesoscale meteorology , environmental science , wind speed , tropical wave , oceanography , geography , meteorology , convection , field programmable gate array , computer science , computer hardware
Climatological features of tropical cyclones in the South Pacific Ocean have been analyzed based on a new archive for the Southern Hemisphere. A vortex tracking and statistics package is used to examine features such as climatological maps of system intensity and the change in intensity with time, average tropical cyclone system movement, and system density. An examination is presented of the spatial variability of these features, as well as changes in relation to phase changes of the El Niño–Southern Oscillation phenomenon. A critical line is defined in this study based on maps of cyclone intensity to describe the statistical geographic boundary for cyclone intensification. During El Niño events, the critical line shifts equatorward, while during La Niña events the critical line is generally displaced poleward. Regional variability in tropical cyclone activity associated with El Niño–Southern Oscillation phases is examined in relation to the variability of large-scale atmospheric or oceanic variables associated with tropical cyclone activity. Maps of the difference fields between different phases of El Niño–Southern Oscillation are examined for sea surface temperature, vertical wind shear, lower-tropospheric vorticity, and midtropospheric relative humidity. Results are also examined in relation to the South Pacific convergence zone. The common region where each of the large-scale variables showed favorable conditions for cyclogenesis coincided with the location of maximum observed cyclogenesis for El Niño events as well as for La Niña years.