ENSO amplitude changes due to climate change projections in different coupled models

Sang Wook Yeh, Benjamin Kirtman

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Four climate system models are chosen here for an analysis of ENSO amplitude changes in 4 × CO2 cimate change projections. Despite the large changes in the tropical Pacific mean state, the changes in ENSO amplitude are highly model dependant. To investigate why similar mean state changes lead to very different ENSO amplitude changes, the characteristics of sea surface temperature anomaly (SSTA) variability simulated in two coupled general circulation models (CGCMs) are analyzed: the Meteorological Research Institute (MRI) and Geophysical Fluid Dynamics Laboratory (GFDL) models. The skewed distribution of tropical Pacific SSTA simulated in the MRI model suggests the importance of nonlinearities in the ENSO physics, whereas the GFDL model lies in the linear regime. Consistent with these differences in ENSO regime, the GFDL model is insensitive to the mean state changes, whereas the MRI model is sensitive to the mean state changes associated with the 4 × CO2 scenario. Similarly, the low-frequency modulation of ENSO amplitude in the GFDL model is related to atmospheric stochastic forcing, but in the MRI model the amplitude modulation is insensitive to the noise forcing. These results suggest that the understanding of changes in ENSO statistics among various climate change projections is highly dependent on whether the model ENSO is in the linear or nonlinear regime.

Original languageEnglish (US)
Pages (from-to)203-217
Number of pages15
JournalJournal of Climate
Volume20
Issue number2
DOIs
StatePublished - Jan 15 2007
Externally publishedYes

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El Nino-Southern Oscillation
climate change
fluid dynamics
temperature anomaly
sea surface temperature
nonlinearity
general circulation model
physics
laboratory
meteorological research
climate

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

ENSO amplitude changes due to climate change projections in different coupled models. / Yeh, Sang Wook; Kirtman, Benjamin.

In: Journal of Climate, Vol. 20, No. 2, 15.01.2007, p. 203-217.

Research output: Contribution to journalArticle

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