Estimating modes of inter-decadal variability and predictability in coupled climate models

Abstract

A methodology is described that allows a separation of inter-decadal variability into components associated with intra-decadal noise and potentially predictable slow decadal processes. The method is applied to a 1200 year simulation of internal variability of sea surface temperature in a coupled atmosphere-ocean model using parameters and radiative forcing associated with the year 2000. The analysis shows large predictability in the extratropical regions. The two leading modes associated with intra-decadal variability are shown to be related to interannual variability in the El Nino--Southern Oscillation and the Atlantic Multi-decadal Oscillation. The leading four slow modes are shown to be related to slow decadal variability in the Pacific Decadal Oscillation, the Atlantic Multi-decadal Oscillation and the Arctic Oscillation. References

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