Figure 1.
SSA reconstructed signals from HadCRUT4 global surface temperature anomalies.
The annual surface temperature (gray line), multidecadal variability (MDV, blue line), secular trend (ST, red line) and reconstructed signal (MDV+ST, black line) are indicated. ST represents 78.8% of the total energy of the series; MDV accounts for 8.8% of the energy and the reconstructed signal for 88%. The dashed thin red lines indicate the range of variability of the ST obtained by applying SSA to the temperature time series obtained for each individual month.
Figure 2.
Singular spectrum analysis of the GMTA.
a) Energy diagram of the first 20 eigenvectors (EV) obtained from the SSA. The horizontal dashed line indicates the 1% energy limit. b) Residuals obtained by removing the signals associated with the first four EV from the original GMTA record. The black bold line represents the linear fit (not significant, p>0.05). c) Autocorrelation analysis of the residuals. The horizontal dashed lines indicate significant bounds.
Figure 3.
a) Warming rates (°C year−1) obtained from the different signals identified in the SSA: ST (red line), MDV (blue line) and reconstructed signal (black line). The dashed thin red lines are the confidence intervals for the warming rate associated with the ST obtained from each individual month’s time series. b) Zoom on the last 25 years of the time series.
Figure 4.
SSA reconstructed signals for Northern Hemisphere surface temperature.
a) HadCRUT4 annual surface temperature (gray line), multidecadal variability (MDV, blue line), secular trend (ST, red line) and reconstructed signal (MDV+ST, black line). The dashed thin red lines indicate the range of variability of the ST obtained by applying SSA to the temperature time series obtained for each individual month. b) Warming rates (°C year−1) obtained from the different signals identified in the SSA for the Northern Hemisphere. The dashed thin red lines are the confidence intervals for the warming rate associated with the ST obtained from each individual month’s time series. c) Zoom on the last 25 years of the warming rate time series.
Figure 5.
SSA reconstructed signals for Southern Hemisphere surface temperature.
a) HadCRUT4 annual surface temperature (gray line), multidecadal variability (MDV, blue line), secular trend (ST, red line) and reconstructed signal (MDV+ST, black line). The dashed thin red lines indicate the range of variability of the ST obtained by applying SSA to the temperature time series obtained for each individual month. b) Warming rates (°C year−1) obtained from the different signals identified in the SSA for the Southern Hemisphere. The dashed thin red lines are the confidence intervals for the warming rate associated with the ST obtained from each individual month’s time series. c) Zoom on the last 25 years of the warming rate time series.