2024-03-29T15:30:27Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/759522016-02-17T16:10:36Zcom_10261_39226com_10261_8col_10261_42742
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Karnauskas, Kristopher B.
author
Smerdon, Jason E.
author
Seager, Richard
author
González-Rouco, J. F.
author
2012-09-01
Internal climate variability at the centennial time scale is investigated using long control integrations from three state-of-the-art global coupled general circulation models. In the absence of external forcing, all three models produce centennial variability in the mean zonal sea surface temperature (SST) and sea level pressure (SLP) gradients in the equatorial Pacific with counterparts in the extratropics. The centennial pattern in the tropical Pacific is dissimilar to that of the interannual El Niño-Southern Oscillation (ENSO), in that the most prominent expression in temperature is found beneath the surface of the western Pacific warm pool. Some global repercussions nevertheless are analogous, such as a hemispherically symmetric atmospheric wave pattern of alternating highs and lows. Centennial variability in western equatorial Pacific SST is a result of the strong asymmetry of interannual ocean heat content anomalies, while the eastern equatorial Pacific exhibits a lagged, Bjerknes-like response to temperature and convection in the west. The extratropical counterpart is shown to be a flux-driven response to the hemispherically symmetric circulation anomalies emanating from the tropical Pacific. Significant centennial-length trends in the zonal SST and SLP gradients rivaling those estimated from observations and model simulations forced with increasing CO2 appear to be inherent features of the internal climate dynamics simulated by all three models. Unforced variability and trends on the centennial time scale therefore need to be addressed in estimated uncertainties, beyond more traditional signal-to-noise estimates that do not account for natural variability on the centennial time scale.
Karnauskas, Kristopher B., Jason E. Smerdon, Richard Seager, Jesús Fidel González-Rouco, 2012: A Pacific Centennial Oscillation Predicted by Coupled GCMs*. Journal of Climate, 25, 5943–5961. doi: http://dx.doi.org/10.1175/JCLI-D-11-00421.1
http://hdl.handle.net/10261/75952
10.1175/JCLI-D-11-00421.1
Oscillations
Climate change
Ocean temperature
Sea level
General circulation model (GCM)
Pacific Area
A Pacific Centennial Oscillation Predicted by Coupled GCMs