Influence of ENSO on the Pacific decadal oscillation in CMIP models
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Emerging decadal climate predictions call for an assessment of decadal climate variability in the Coupled Model Intercomparison Project (CMIP) database. In this paper, we evaluate the influence of El Niño Southern Oscillation (ENSO) on Pacific Decadal Oscillation (PDO) in 10 control simulations from the CMIP3 and 22 from the CMIP5 database. All models overestimate the time lag between ENSO forcing and the PDO response. While half of the models exhibit ENSO-PDO correlation which is close to that in observation (>0.5) when the time lag is accounted for, the rest of the models underestimate this relationship. Models with stronger ENSO-PDO correlation tend to exhibit larger PDO-related signals in the equatorial and south Pacific, highlighting the key role of ENSO teleconnection in setting the inter-hemispheric Pacific pattern of the PDO. The strength of the ENSO-PDO relationship is related to both ENSO amplitude and strength of ENSO teleconnection to the North Pacific sea-level pressure variability in the Aleutian Low region. The shape of the PDO spectrum is consistent with that predicted from a combination of direct ENSO forcing, atmospheric stochastic forcing over the North Pacific and the re-emergence process in 27 models out of 32. Given the essential role of ENSO in shaping the Pacific decadal variability, models displaying realistic ENSO amplitude and teleconnections should be preferentially used to perform decadal prediction experiments.
KeywordsENSO PDO Decadal variability Climate CMIP
The lead author is supported by financial assistance and research facilities of CSIR-NIO, India. This research was sponsored under the Agence Nationale pour la Recherche (ANR) MORDICUS project ANR-13-SENV-0002. This work was done while ML was a visiting scientist at the CSIR-NIO, under Institut de Recherche pour le Développement (IRD) funding. JV and TI also acknowledge IRD support for regular visits to CSIR-NIO. We thank the anonymous reviewer for the valuable comments that helped to improve the manuscript. This is CSIR-NIO contribution No. 5980.
- Cleveland RB, Cleveland WS, McRae JE, Terpenning I (1990) STL: a seasonal-trend decomposition procedure based on loess. J Off Stat 6:3–73Google Scholar
- Newman M, Compo GP, Alexander MA (2003) ENSO-forced variability of the Pacific decadal oscillation. J Climate 16(23)Google Scholar
- Wu L, Liu Z, Gallimore R et al (2003) Pacific decadal variability: The tropical Pacific mode and the North Pacific mode. J Climate 16(8)Google Scholar
- Yin X, Gleason BE, Compo GP, Matsui N (2008) The International Surface Pressure Databank (ISPD) land component version 2.2., National Climatic Data Center, Asheville, NC, pp 1–12, 2008Google Scholar