A new index for variations in the position of the South Pacific convergence zone 1910/11-2011/2012

Salinger, M. J. and McGree, Simon and Beucher, Florent and Power, Scott B. and Delage, Francois (2014) A new index for variations in the position of the South Pacific convergence zone 1910/11-2011/2012. Climate Dynamics, 43 (3-4). pp. 881-892. ISSN 0930-7575


Abstract

Quality controlled and recently homogenised mean sea level pressure records for the South Pacific are used to specify the location and variability of the South Pacific convergence zone (SPCZ) during the austral warm season (November-April). The SPCZ is the world's largest rainfall band during the austral summer, when it dominates the climate of the South Pacific. A new index called the South Pacific convergence zone index (SPCZI) is derived, and is shown to be coherent with changes in low level wind convergence associated with the SPCZ. This index replaces the earlier SPCZ position index because it uses higher quality mean sea level pressure data than the superseded index and extends the time series further forward in time. The SPCZI allows interannual to decadal variability in the climate of the South Pacific to be tracked for more than a century from 1910/1911 to 2011/2012. During El Niño episodes the SPCZ is displaced by about 1°-3° east, and La Niña events 1°-3° west of the mean position on average. The index indicates a striking movement eastward for the period 1977/78-1998/99, compared with 1944/45-1976/77 in association with the Interdecadal Pacific oscillation (IPO). The eastward movement of the SPCZ in the late twentieth century is related to significant precipitation trends in the South Pacific region. Since 1998/99 the SPCZ has regressed westward with the negative phase change of the IPO. The long-term trend in the SPCZI is very small relative to the interannual to decadal variability and is not statistically significant, suggesting that there has been little overall change in the mean position of the SPCZ over the past century. © 2014 Springer-Verlag Berlin Heidelberg.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 24 Nov 2021 06:31
Last Modified: 24 Nov 2021 06:39
Uncontrolled Keywords: air-sea interaction; climate variability; El Nino; Interdecadal Pacific Oscillation; La Nina; New index; South Pacific convergence zone
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: https://doi.org/10.1007/s00382-013-2035-y
URI: http://eprints.usq.edu.au/id/eprint/42429

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