“…SSA (Colebrook, 1978;Broomhead and King, 1986;Fraedrich, 1986;Vautard and Ghil, 1989;Ghil and Vautard, 1991;Vautard et al, 1992) -a form of temporal PC or EOF analysis -was used for both prefiltering and the long-term analysis of the filtered time series. SSA is a powerful form of PC analysis of the lag-correlation structute of time seiles (Vautard et al, 1992; that is particularly successful in isolating multiple periodic components and trends in short, noisy seiles. SSA has been applied to univariate time series (e.g., Ghil and Mo, 1991a, b;Keppenne and Ghil, 1992;Plaut et al, 1995), to spatially correlated series (Kimoto et al, 1991;Keppene and Ghil, 1993;Plaut and Vautard, 1994), and, in this study, to uncorrelated series.…”