Representation of the ocean's multidecadal variability in CMIP5 runs.

Ocean shapes the variability of the global surface temperature to the large extent. It contributes also to the recently observed global warming hiatus, with the fingerprint of cooling over tropical Eastern Pacific, not captured by most of the historical simulations of climate models.

In this study, the observed and simulated by climate models variability of the ocean on decadal/multidecadal time scale is analysed. Multi-Channel Singular Spectrum Analysis (MCSSA) is applied to the output of the long CMIP5 control-runs, to derive robust features of the unforced, low-frequency temperature oscillations. Spatio-temporal signature, of the variability detected in several models, suggests a remarkable contribution of the unforced components to the observed multi-decadal variability including hiatus periods in 1950-1970s and 1990-2000s.