RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION

A 200-yr long coupled general circulation model (CGCM) simulation is used to investigate the characteristics and impact of the low frequency variability of the equatorial background stratification on the ENSO modulation. A vertical mode decomposition of the model mean vertical structure is performed...

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Main Authors: Boris Dewitte, Sang-Wook Yeh, Carole Cibot, Laurent Terray
Format: Article
Language:English
Published: Universidad de Concepción 2004-01-01
Series:Gayana
Online Access:http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000200028
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author Boris Dewitte
Sang-Wook Yeh
Carole Cibot
Laurent Terray
author_facet Boris Dewitte
Sang-Wook Yeh
Carole Cibot
Laurent Terray
author_sort Boris Dewitte
collection DOAJ
description A 200-yr long coupled general circulation model (CGCM) simulation is used to investigate the characteristics and impact of the low frequency variability of the equatorial background stratification on the ENSO modulation. A vertical mode decomposition of the model mean vertical structure is performed and the interdecadal variability of the baroclinic mode parameters is analyzed. The low frequency variations of the baroclinic mode parameters associated to the decadal mode in the model are then used to force an intermediate coupled anomaly model "tuned" with the CGCM derived climatologies and wave parameters. Results of sensitivity experiments indicate that a rectification of the interannual variability (ENSO timescales) by the interdecadal variability associated to changes in the oceanic mean states does take place. However, the magnitude and characteristics of this rectification highly depends on the strength of the interaction between the ENSO mode and the seasonal cycle. Implications for ENSO decadal predictability is then discussed
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spelling doaj.art-39c5eaccaee542798cefb8dd87f66afe2022-12-21T19:24:00ZengUniversidad de ConcepciónGayana0717-652X0717-65382004-01-01682151156RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATIONBoris DewitteSang-Wook YehCarole CibotLaurent TerrayA 200-yr long coupled general circulation model (CGCM) simulation is used to investigate the characteristics and impact of the low frequency variability of the equatorial background stratification on the ENSO modulation. A vertical mode decomposition of the model mean vertical structure is performed and the interdecadal variability of the baroclinic mode parameters is analyzed. The low frequency variations of the baroclinic mode parameters associated to the decadal mode in the model are then used to force an intermediate coupled anomaly model "tuned" with the CGCM derived climatologies and wave parameters. Results of sensitivity experiments indicate that a rectification of the interannual variability (ENSO timescales) by the interdecadal variability associated to changes in the oceanic mean states does take place. However, the magnitude and characteristics of this rectification highly depends on the strength of the interaction between the ENSO mode and the seasonal cycle. Implications for ENSO decadal predictability is then discussedhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000200028
spellingShingle Boris Dewitte
Sang-Wook Yeh
Carole Cibot
Laurent Terray
RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION
Gayana
title RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION
title_full RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION
title_fullStr RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION
title_full_unstemmed RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION
title_short RECTIFICATION OF THE ENSO VARIABILITY BY INTERDECADAL CHANGES IN THE EQUATORIAL BACKGROUND MEAN STATE IN A CGCM SIMULATION
title_sort rectification of the enso variability by interdecadal changes in the equatorial background mean state in a cgcm simulation
url http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000200028
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AT sangwookyeh rectificationoftheensovariabilitybyinterdecadalchangesintheequatorialbackgroundmeanstateinacgcmsimulation
AT carolecibot rectificationoftheensovariabilitybyinterdecadalchangesintheequatorialbackgroundmeanstateinacgcmsimulation
AT laurentterray rectificationoftheensovariabilitybyinterdecadalchangesintheequatorialbackgroundmeanstateinacgcmsimulation