Climate Dynamics

, Volume 35, Issue 2, pp 299–313

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

Article

DOI: 10.1007/s00382-009-0562-3

Cite this article as:
Lengaigne, M. & Vecchi, G.A. Clim Dyn (2010) 35: 299. doi:10.1007/s00382-009-0562-3

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.

Keywords

El Niño/Southern Oscillation (ENSO)Extreme eventsIPCC-AR4 climate modelsCoupled ocean–atmosphere mechanismsValidation

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Institut de Rechrche pour le Developpement/Laboratoire d’Oceanographie et de Climatologie, Experimentations et Approches NumériquesParis Cedex 05France
  2. 2.NOAA/Geophysical Fluid Dynamics LaboratoryPrincetonUSA