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Short Term Auto Correlation

Notes:

Evenly spaced correlation peaks every 200 years would seem to indicate a 200 year periodic effect. However, this is a multiple of the internal time tic (50 years) and the maximum anti-correlation peak at 100 years means that if the temperature is changing, there's a high probability that the change will be reversed within 100 years. When 200 year smoothing is applied, this becomes a smaller, 400 year periodic effect and when smaller buckets are used, the period becomes shorter. All of these are strong indications of aliasing to shorter period effects. The peak at 0 is 100% (off scale), which means that it's 100% correlated to itself.

When 700 year smoothing is applied, there are no discernible short term peaks in the correlation function, although the temperature plot shows small, somewhat chaotic variability cycling over 700-1200 years. The specific recent temperature variability from this effect seems to correspond to Maunder minimums and maximums.

When 1500 year smoothing is applied, the 22K, 41K, 96K and 500K periodic effects related to orbit and axis variability emerge.