Climate Audit

In order to illustrate a useful application of principal components, Tamino showed coordinate systems for the motion of a canoe. In the context of MBH, it would have been more instructive to show how principal components apply to tree ring networks than to canoes. In such a context,a non-Mannian centered PC1 will typically show some sort of weighted average and lower PCs will show contrasts, which feature increasingly trivial and local contrasts. I’ll show this in connection with the Stahle SWM network used in MBH98, where there is relatively little difference between Mannian and centered PCs and which will give readers a flavor of exactly how little utility the lower order PCs have.

Readers may also consider the following assumption underlying MBH:

Implicit in our approach are at least three fundamental assumptions. (1) The indicators in our multiproxy trainee network are linearly related to one or more of the instrumental…

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