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 […]
Hansen’s twin pit bulls, Tamino and Gavin, have launched into a spirited defence of Mannian paleo-phrenology at realclimate here, with a counter-discussion at Bishop Hill here.
Date: 16 Nov 1999, Phil I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith’s to hide the decline. Date: 22 Dec 2004, mike No researchers in this field have ever, to our knowledge, “grafted […]
Just when you thought that there was nothing left to say about MBH98, look at this MBH98 "flavor" that the cat dragged in today. This is a MBH-flavor reconstruction using MBH methodology and MBH proxies, following one of the NAS panel suggestions!! What did I do? Figure 1. A New MBH98 Flavor
I’ve posted in the past on the mystery of MBH confidence interval calculations, especially the mysterious MBH99 confidence intervals (another Caramilk secret). In our NAS panel presentation and perhaps before, I’d speculated that MBH98 confidence intervals, rotundly described in MBH98 as “self-consistently estimated”, were nothing other than twice the standard error of the (overfitted) calibration […]
Climate Audit 