Statistical Results from Original Stadium-Wave analysis, given here for comparison to model results. (a) Shows individual variances (%) and (b) cumulative variances (% of the total) of the modes of variability shared by the collection of eight instrumental climate indices. The M-SSA window size is M=20. The error bars in (a) are based on (North et al. 1982) criterion, with the number of degrees-of-freedom set to 40, based on the decorrelation time scale of ~2.5 years. The red lines in panel (a) represent the 95% spread of M-SSA eigenvalues based on 100 simulations of the eight-valued red-noise model (1), which assumes zero true correlations between the members of the eight-index set. Note the leading two modes of variability; they are widely separated from the remaining modes; their error bars overlap. (c) Depicts reconstructed components (RCs) for each of the eight modes of variability derived. RCs of the leading modes show similar variability. (d) Normalized reconstructed components (RCs) of M-SSA leading two modes of variability are plotted. Note that each index carries this signal, and that the signal propagates through the network of regionally diverse indices. (Adapted from Wyatt et al. 2011). RC time series have been normalized to have unit variance. Note: RCs of NHT and AMO are negative.