Tag Archives: upside down

More Upside-Down Mann

Previously, we discussed the upside-down Tiljander proxies in Mann et al 2008. Ross and I pointed this out in our PNAS comment, with Mann denying in his answer that they were upside down. This reply is untrue (as Jean S and UC also confirmed.) Andy Baker’s SU967 proxy is used in Mann 2008 and is […]

More Z-Score Opportunism

We’ve frequently observed that the reduction of data to standard deviation units (z-scores) is often associated with seemingly opportunistic orientation of the data sets. Often this is buried in the multivariate methodology. Principal components and RegEM can both function to opportunistically provide orientations to “proxies”. In Mann 2008, we saw pretty examples of proxies being […]

Upside-Down Quadratic Proxy Response

David Stockwell has suggested a discussion of nonlinear responses of tree growth to temperature. I’ve summarized here some observations which I’ve seen about bristlecones, limber pine, cedars and spruce – all showing an upside-down U-shaped response to temperature. The implications of this type of relationship for the multiproxy project of attempting to reconstruct past temperatures […]

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