I’ve used SSA analysis to extract the first mode from the northern hemisphere SST record available from http://www.metoffice.gov.uk/hadobs/hadsst3/data/HadSST.22.214.171.124/HadSST3_annual_nh _ts.txt”
The plot above shows the dominate eigen mode plotted with the detrended SST data. The plot below show the mode plotted against a sine wave fit.
The best fit period is about 64 years and shows signs of slight phase modulation. At first I thought difference in frequency between this mode and the similar mode extracted from the Hadcrut3 surface temperature data pointed away from a celestial forcing. Then I decided to look at correlations between the two.
Here’s the auto-correlation of the Hadcrut3 climate signal reconstructed from the first eigenpair,It shows cyclostationarity with a period of ~57 years, similar to what was found by harmonic decomposition. Here’s the ACF of the same mode extracted from the SST northern hemisphere data. Here’s both on the same plot
This is pretty convincing evidence that the mode in both datasets have the same period (56.8 years).
The cross correlation shows global surface temperature 4.2 years lags the sea surface temperature by 4.2 years.
The cross spectrum is pretty amazing
And then there is this: