Contrasting the termination of moderate and extreme El Niño events in coupled general circulation models

Matthieu Lengaigne, Gabriel Andres Vecchi

Research output: Contribution to journalArticle

51 Scopus citations

Abstract

As in the observed record, the termination of El Niño in the coupled IPCC-AR4 climate models involves meridional processes tied to the seasonal cycle. These meridional processes both precondition the termination of El Niño events in general and lead to a peculiar termination of extreme El Niño events (such as those of 1982-83 and 1997-98), in which the eastern equatorial Pacific warm sea surface temperature anomalies (SSTA) persist well into boreal spring/early-summer. The mechanisms controlling the peculiar termination of extreme El Niño events, which involves to the development of an equatorially centred intertropical convergence zone, are consistent across the four models that exhibit extreme El Niños and observational record, suggesting that this peculiar termination represents a general feature of extreme El Niños. Further, due to their unusual termination, extreme El Niños exhibit an apparent eastward propagation of their SSTA, which can strongly influence estimates of the apparent propagation of ENSO over multi-decadal periods. Interpreting these propagation changes as evidence of changes in the underlying dynamical feedbacks behind El Niño could therefore be misleading, given the strong influence of a single extreme event.

Original languageEnglish (US)
Pages (from-to)299-313
Number of pages15
JournalClimate Dynamics
Volume35
Issue number2
DOIs
StatePublished - Jan 1 2010

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Keywords

  • Coupled ocean-atmosphere mechanisms
  • El Niño/Southern Oscillation (ENSO)
  • Extreme events
  • IPCC-AR4 climate models
  • Validation

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