213:. During El Niño or warm-phase conditions, the SPCZ typically shifted northeastward with dryer conditions on islands to the southwest, in agreement with observations. Conversely, a southwestward shift in rainfall accompanied La Niña or cold-phase events in the simulations. Widlanksy et al. (2012) argued the sea surface temperature biases in models created uncertainty in the rainfall projections and produce what has been named “the double ITCZ problem”. The impact of sea surface temperature bias was further investigated by using uncoupled atmospheric models with prescribed sea surface temperatures, and those 3 models each with differing complexity showed less severe double ITCZ bias than the ensemble of coupled models.
186:. Coral isotope measurements provide information on both sea surface temperature and sea surface salinity, so they can indicate times of increased or decreased temperature and/or precipitation associated with changes in the position of the SPCZ. Their coral oxygen isotope index indicated an eastward shift of the decadal mean position of the SPCZ since the mid 1800s. A shift of the SPCZ in this direction suggests there were more La Niña-like or cold-phase conditions in the Pacific, during this period, often called the
170:(ENSO) and can also describe movements of the position of the SPCZ. Negative SOI index values are associated with warm-phase or El Niño-like conditions and a northeastward displacement of the SPCZ. Positive SOI index values, on the other hand, describe cold-phase or La Niña-like conditions and a southwestward displacement of the SPCZ.
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Determining the position of the SPCZ over longer timescales in the past (pre-20th century) has been studied using coral records of the southwest
Pacific. Linsley et al. (2006) reconstructed sea-surface temperature and sea surface salinity in the southwest Pacific starting circa 1600CE by measuring
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to the south meet with the semipermanent easterly flow from the eastern South
Pacific anticyclone. The SPCZ exists in summer and winter but can change its orientation and location. It is often distinct from the ITCZ over Australia, but at times they become one continuous
112:. Thunderstorm activity, or convection, within the band is dependent upon the season, as the more equatorward portion is most active in the Southern Hemisphere summer, and the more poleward portion is most active during transition seasons of fall and spring. The
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and night marine air temperature to determine how the SPCZ varies with the IPO. When the IPO index has negative temperature anomalies, the SPCZ is displaced southwest and moves northeastward when the IPO index has positive temperature anomalies. The
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The climatological position can be estimated by computing its mean position over 30 or more years. There are several metrics to measure the position of the SPCZ. The location of maximum rainfall, maximum of low level
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At its southeast edge, the circulation around the feature forces a salinity gradient in the ocean, with fresher and warmer waters of the western
Pacific lying to its west. Cooler and saltier waters lie to its east.
51:. The SPCZ can affect the precipitation on Polynesian islands in the southwest Pacific Ocean, so it is important to understand how the SPCZ behaves with large-scale, global climate phenomenon, such as the ITCZ,
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197:) and IPO strongly influence the SPCZ latitude, but farther east only ENSO is a significant factor. Only near 170 W is there any indication of an interaction between the two factors.
47:. It is considered the largest and most important piece of the ITCZ, and has the least dependence upon heating from a nearby landmass during the summer than any other portion of the
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of differing complexity to simulate rainfall bands in the southwest
Pacific and see how the magnitude and areal extent was affected by the SPCZ and
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Besides observations of the SPCZ and movement in its position, there have been modelling studies as well. Widlansky et al. (2012) used a number of
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Research into SPCZ movements of the 20th century are linked to changes in the IPO and ENSO. Folland et al., 2002 defined an index to describe the
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The IPO and ENSO can interact together to produce changes in the position of the SPCZ. West of about 140 W, both ENSO (measured with
43:(ITCZ) which lies in a band extending east–west near the Equator but can be more extratropical in nature, especially east of the
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137:(OLR) are four indicators of the SPCZ axis. Figure 1 shows qualitative agreement between all of these SPCZ indicators.
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487:"Relative influences of the Interdecadal Pacific Oscillation and ENSO in the South Pacific Convergence Zone"
349:"Relative influences of the Interdecadal Pacific Oscillation and ENSO in the South Pacific Convergence Zone"
190:. Additional paleoclimate studies are still needed in order to test the reliability of these coral results.
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437:, Karl Stein, Shayne McGregor, Niklas Schneider, Matthew H. England, Matthieu Lengaigne, and Wenju Cai.
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An observational study of the South
Pacific Convergence Zone using satellite and model re-analysis data
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The position of the SPCZ can change on seasonal, interannual, and possibly longer timescales.
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Polynesia and as far as the
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Tracking the extent of the South
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shifts east or west depending on the existence of El Niño, or the phase of
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Tropical textbook : from trade winds to cyclone (2 vol)
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Changes in South
Pacific rainfall bands in a warming climate
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The SPCZ occurs where the southeast trades from transitory
464:, 897 pp., Florent Beucher, 25 mai 2010, Météo-France,
406:Braddock K. Linsley, Alexey Kaplan, Yves Gouriou,
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277:Movement of the South Pacific Convergence Zone.
315:(PhD dissertation). Texas A&M University.
88:conditions. It generally stretches from the
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155:Interdecadal Pacific oscillation
86:Interdecadal Pacific oscillation
57:Interdecadal Pacific oscillation
309:Cocks, Stephen Brenton (2003).
290:South Pacific convergence zone.
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481:C. K. Folland, J. A. Renwick,
343:C. K. Folland, J. A. Renwick,
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41:Intertropical Convergence Zone
21:South Pacific Convergence Zone
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491:Geophysical Research Letters
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53:El Niño–Southern Oscillation
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195:Southern Oscillation Index
164:Southern Oscillation Index
288:Glossary of Meteorology.
33:Western Pacific Warm Pool
554:Regional climate effects
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421:Retrieved on 2006-11-26.
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279:Retrieved on 2006-11-26.
141:Changes in SPCZ position
59:(IPO), a portion of the
485:, A. B. Mullan (2002).
347:, A. B. Mullan (2002).
159:sea surface temperature
124:Measuring SPCZ position
45:International Date Line
433:Matthew J. Widlansky,
27:), a reverse-oriented
16:Seasonal storm pattern
559:Physical oceanography
242:Tropical cyclogenesis
549:Atmospheric dynamics
544:Tropical meteorology
512:10.1029/2001GL014201
374:10.1029/2001GL014201
217:Related oceanography
503:2002GeoRL..29.1643F
365:2002GeoRL..29.1643F
178:coral records from
78:zone of convergence
417:2011-06-06 at the
295:2007-09-30 at the
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359:(13): 21–1–21–4.
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55:, and the
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