Global surface temperature anomaly in °C from 1855 through 1989, together with spectral oscillations derived from it determined from the maximum entropy spectrum. Panel 1: Smoothed and detrended temperature anomaly obtained by subtracting from the smooth curve of Figure 3 a spline fit to the yearly averaged anomaly data with a s of 0.106°C, as in curve 1 of Figure 4. Panel 2: Sum of 24 spectral oscillations derived from a fit to the curve in panel 1, which are consistent with the spectral peaks as listed in Table 1, column 2. Panel 3: Sum of decadal oscillations. Panel 4: Sum of bidecadal oscillations. Panel 5: Sum of eight oscillations with periods of 6.67 calendar years or greater (no exclusions). The source of the temperature data is the same as in Figure 3. The time of maximum interference of the decadal oscillations in panel 3 is indicated.