ClimateBallers are extremely suspicious of the MM05 simulation methodology, to say the least. A recurrent contention is that we should have removed the climate “signal” from the NOAMER tree ring network before calculating parameters for our red noise simulations, though it is not clear how you would do this when you not only don’t know the true “signal”, but its estimation is the purpose of the study.
In MM05, we quantified the “hockeystick-ness” of a series as the difference between the 1902-1980 mean (the “short centering” period of Mannian principal components) and the overall mean (1400-1980), divided by the standard deviation – a measure that we termed its “Hockey Stick Index (HSI)”. The histograms of its distribution for 10,000 simulated networks (shown in MM05 Figure 2) were the primary diagnostic in MM05 for the bias in Mannian principal components.
In MM05, we quantified the hockeystick-ness of simulated PC1s as the difference between the 1902-1980 mean (the “short centering” period of Mannian principal components) and the overall mean (1400-1980), divided by the standard deviation – a measure that we termed its “Hockey Stick Index (HSI)”. In MM05 Figure 2, we showed histograms of the HSI distributions of Mannian and centered PC1s from 10,000 simulated networks.
