Category Archives: Juckes et al 2006

The "Independent" 2006 Multiproxy Studies

Here’s a quick summary of the overlap of proxies in three widely publicized “independent” 2006 studies. The number of proxies are all small (Juckes -18; Osborn – 14; Hegerl – 12). All three use multiple bristlecone/foxtail chronologies: Juckes 4; OSborn 2; Hegerl 2. All three use Fisher’s Greenland dO18, Tornetrask (Juckes twice, Hegerl mis-identifying it); […]

Juckes and the David Black Condemnation

I’ve written on several occasions about Juckes’ use of cold water G Bulloides as a supposed temperature proxy (following Moberg’s equally indefensible use of this proxy.) It has come to my attention that a leading specialist, David Black of the University of Akron, had already issued a scathing denunciation of Juckes’ use of G Bulloides […]

Juckes and the Rain in Maine

Juckes stated: MM2003 criticise MBH1998 on many counts, some related to deficiencies in the description of the data used and possible irregularities in the data itself. These issues have been largely resolved in Mann et al. (2004) [the Corrigendum]. Did Juckes carry out any due diligence in order to make the latter statement? Because I’m […]

Overfitting by Inverse Regression

Wahl and Ammann 2006 reported that they could “get” something that was sort of HS-ish without principal component analysis. It wasn’t through a simple mean or CVM; it was through Mannian inverse regression. Juckes et al shows many reconstructions using “inverse regression”, mentioning in his conclusions that inverse regression caused over-concentration on a few proxies. […]

Juckes – Meet the Durbin-Watson Statistic

When one looks at the plots of the various Juckes proxies against gridcell temperature, the possibility of spurious regression must come to mind. “Spurious regression” has been discussed on this blog from time to time and tries to provide a statistical framework for seemingly high correlations between unrelated series – things like Honduran births and […]

The Juckes Proxies

I thought that some of you would be interested in a plot of Juckes’ Union proxies against gridcell temperatures. I’ll start off by simply showing a plot during the 1856-1980 calibration period (both scaled over 1856-1980), as below, followed by a plot of the residuals. The proxies are arranged according to longitude from California going […]

Replicating Juckes' CVM

Here are some notes on my attempts to replicate Juckes’ CVM calculations, together with a script. I can replicate some reconstructions very closely – e.g. Esper and Jones within less than a tenth of a degree of the archived CVM, but other replications,including the Union reconstruction, are not as close. In each case, I checked […]

Juckes cites Wahl and Ammann

One of the really annoying things about Wahl and Ammann was their failure to cite our prior analysis of various MBH permutations and, then, having failed to cite these prior analyses, reproaching us for supposedly “omitting” these analyses. For example, in MM05 (EE) we discussed the relative impact of using 2 or 5 covariance PC2 […]

Juckes and Covariance PCs

Juckes and the Euro Team spent a lot of time on the topic of MM normalization, stating as follows (continuing the academic check kiting initiated by claims made in Wahl and Ammann (Clim Chq 2006) using the rejected Ammann and Wahl (GRL 2006)): Wahl and Ammann (2006) ascribe the difference between MM2005 and MBH1998 to […]

Juckes and the Pea under the Thimble (#1)

Juckes has much to say about several MM articles, none of it favorable and little of it accurate. Juckes, like the rest of the Team, seldom quotes our articles – instead, he typically paraphrases what we said, often creating a straw man, which he prefers to deal with. It’s a wearisome task disentangling the many […]