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Extreme swings of the South Pacific Convergence Zone and the different types of El Niño events
Author(s) -
Borlace Simon,
Santoso Agus,
Cai Wenju,
Collins Matt
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl060551
Subject(s) - climatology , zonal and meridional , convection , geology , global warming , environmental science , sea surface temperature , magnitude (astronomy) , walker circulation , atmospheric sciences , climate change , oceanography , geography , meteorology , physics , astronomy
There have been three extreme equatorward swings of the South Pacific Convergence Zone (SPCZ) during the satellite era. These zonal SPCZ (zSPCZ) events coincided with an El Niño of different magnitude and spatial pattern, in which strong anomalous warming reduced the off‐equatorial‐to‐equatorial meridional sea surface temperature (SST) gradient near the dateline, enabling convection to shift equatorward. It is not known, given the short observational record, how and whether different types of El Niño are associated with zSPCZ events. Using perturbed physics ensembles experiments in which SST biases are reduced, we find that zSPCZ events are concurrent with notable eastern Pacific (EP) warming. Central Pacific warming alone is rarely able to produce a swing, even as the climate warms under a CO 2 increase scenario. Only El Niño events with strong EP warming can shift the convective zone. Such co‐occurring events are found to increase in frequency under greenhouse warming.