Quasi-decadal and inter-decadal climate fluctuations in the Pacific Ocean from a CGCM

• Published in: Geophysical Research Letters
• Main Authors: Tourre, Yves M., Cibot, Carole, Terray, Laurent, White, Warren B., Dewitte, Boris
• Other Authors: Mediterranée et Afrique Subtropicale-France (MEDIAS-France), Centre National d'Études Spatiales Toulouse (CNES), Lamont-Doherty Earth Observatory (LDEO), Columbia University New York, Météo-France Paris, Météo France, Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, Scripps Institution of Oceanography (SIO), University of California San Diego (UC San Diego), University of California-University of California, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: [SDU]Sciences of the Universe [physics]; Pacific; Subarctic
• Online Access: https://hal.archives-ouvertes.fr/hal-00280330; https://hal.archives-ouvertes.fr/hal-00280330/document; https://hal.archives-ouvertes.fr/hal-00280330/file/2004GL022087.pdf; https://doi.org/10.1029/2004GL022087

International audience Diagnostic analyses in the Pacific, have revealed distinct quasi-decadal (QD) and inter-decadal (ID) climate fluctuations with coherent varying patterns of sea surface temperature (SST) and sea level pressure (SLP) anomalies. From a 200-year CGCM simulation, distinct low-frequency fluctuations are also obtained: QD (i.e., 8-12 years period band) and ID (i.e., 18-25 years period band). Traced modeled QD evolution reveals equatorial SST anomalies resembling ENSO, while tropical recharge/discharge mechanisms seem to be operating. The traced modeled ID evolution reveals high latitudes spatially coherent patterns, with maximum SST anomalies in the vicinity of the subarctic frontal zone (SAFZ) and subtropical gyres through advection. Contrary to QD SST anomalies, the modeled ID SST anomalies peak away from the equator as observed. QD fluctuations may then be viewed as low-frequency ENSO phenomena, while ID fluctuations may set-up thermal background modulating frequency and intensity of ENSO.