MBH98 used three Jacoby tree ring chronologies from Alaska: Four Twelve (ak031) – discussed here, Arrigetch (ak032) and Sheenjek (ak033). Sheenjek will be discussed in this article. In our compilation of MBH98 in 2003, we observed that the Sheenjek chronology archived at NOAA Paleo was not the same as the “grey” version used in MBH98. […]
We’ve long discussed the bias imparted by ex post selection of data depending on whether it went up in the 20th century. Likening such after-the-fact selection to a drug study carried out only on survivors. The Jacoby and d’Arrigo 1989 network was a classic example: the original article reported that they had sampled 36 northern treeline […]
In numerous ancient Climate Audit posts, I observed that all MBH98 operations were linear and that the step reconstructions were therefore linear combinations of proxies, the coefficients of which could be calculated directly from the matrix algebra (described in a series of articles.) Soderqvist’s identification of the actual proxies enables calculation of the AD1400 weights […]
In today’s post, I will report on some excellent work on MBH98 by Hampus Soderqvist, who discovered an important but previously unknown Mike’s Nature Trick: Mann’s list of proxies for AD1400 and other early steps was partly incorrect (Nature link now dead – but see NOAA or here). Mann’s AD1400 list included four series that […]
Continued from here. The Dirty Laundry residual datasets for AD1000, AD1400 and AD1600 were each calculated using Mann’s “sparse” instrumental dataset, but the resultant sigmas and RE(calibration) statistics don’t match reported values. In contrast, the Dirty Laundry residual dataset for the AD1820 step, which was calculated by Tim Osborn of CRU because Mann “couldn’t find” […]
As the date approached for the Mann-Steyn/Simberg libel trial, I’ve been reviewing my files on MBH98 and MBH99. It’s about 15 years since I last looked at these issues. While revisiting these issues, I re-examined some data associated with the notorious “dirty laundry” Climategate email (link) – excerpt shown at right – that turns out […]
PCA was also performed on certain proxy sub-networks (spatially dense regional networks of tree-ring data available separately in different continents) as means of dimensional reduction of the predictor network. In this case, the procedure was performed separately for each independent step of the stepwise calibration/reconstruction procedure described in “3” below.
In today’s post, I will return to my series on false claims in Mann’s lawsuit about supposed “exonerations”. ( For previous articles, see here).
