The existence of a problem in one of the above does not exlude possible problems in each of the others.

]]>1. Frequencies are shared by both GISS & UAH, except that GISS’s absolute values are about 1.2 times higher than UAH for some unknown reason (but nothing to do with models). With this alone we would expect a horizontal line at a value of 1.2 .

2. Additional GISS-only noise at frequencies (with a period of) up to approximately 1.5 years. (Of course, rather than just stop suddenly at some point, the noise is likely to reduce gradually, and perhaps not reach a minimum until perhaps 3 years). i.e. The covariance tends to zero for frequencies near zero, as you stated yourself.

3. Both data sets have “detrended the 30 year data so it is forced to drop to a level of 1:1”. Presumably this means that as frequencies come closer to 30 years they both come closer to having zero amplitude, and thus covariance drops to 1.0 . This then gives the gradual down slope after 3 years.

So guess I’m just wondering if this is another “hockey stick algorithm” that produces one shape for any reasonably realistic range of input data (e.g. red noise for condition 1, additional GISS-only white noise for condition 2, and detrended data for condition 3).

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