Portal de Periódicos da CAPES

Representing El Niño in Coupled Ocean–Atmosphere GCMs: The Dominant Role of the Atmospheric Component

2004; American Meteorological Society; Volume: 17; Issue: 24 Linguagem: Inglês

10.1175/jcli-3260.1

1520-0442

Éric Guilyardi, Silvio Gualdi, Julia Slingo, Antonio Navarra, P. Délécluse, Julia E. Cole, Gurvan Madec, Malcolm Roberts, Mojib Latif, Laurent Terray,

Tropical and Extratropical Cyclones Research

Abstract A systematic modular approach to investigate the respective roles of the ocean and atmosphere in setting El Niño characteristics in coupled general circulation models is presented. Several state-of-the-art coupled models sharing either the same atmosphere or the same ocean are compared. Major results include 1) the dominant role of the atmosphere model in setting El Niño characteristics (periodicity and base amplitude) and errors (regularity) and 2) the considerable improvement of simulated El Niño power spectra—toward lower frequency—when the atmosphere resolution is significantly increased. Likely reasons for such behavior are briefly discussed. It is argued that this new modular strategy represents a generic approach to identifying the source of both coupled mechanisms and model error and will provide a methodology for guiding model improvement.