Mission Impossible Team, here’s your assignment today. Unfortunately you failed your last assignment: replicating Mann’s claimed correlations. But that probably was impossible. Today your assignment is probably possible, but is a dangerous expedition into the dark underground – into the terrifying world of Mannian RegEM. Courage and perseverance will be required. You may not return […]
A couple of days ago, I received the Almagre measurement data from the excellent dendrochronological lab at the Univesity of Guelph. I’ve posted the measurement data online in two files (as I received them): crossdated and uncrossdated. There are 41 cores that have been crossdated and 20 cores are not crossdated. These files are as […]
Judith Curry and JEG have expressed an interest in talking about Mann et al 2007, Robustness of proxy-based climate field reconstruction methods, JGR pdf. This is successor article to Mann et al, 2005, Testing the Fidelity of Methods Used in Proxy-Based Reconstructions of Past Climate, pdf. Looking past the annoying and amusing faults, here are some […]
Mann et al 2007 is a new RegEM version, replacing the RegEM calculations of Rutherford et al 2005. The logic is not entirely self-contained and so I re-visited some of our previous comments on Rutherford et al here here here here . I’m going to reprise two issues today: Collation Errors, a small but amusing […]
Ross McKitrick writes: First, on page 15, they say: This result (as well as the separate study by Wahl and Ammann [2007]) thus refutes the previously made claim by MM05 that the features of the MBH98 reconstruction are somehow an artifact arising from the use of PC summaries to represent proxy data. Well, if we […]
Here’s an assignment for JEG’s hockey stick class. Try to replicate the reported proxy-gridcell temperature correlations reported in Mann et al 2007 SI. The table showing correlations between 112 proxies (the AD1820 network presumably) and gridcell temperature are shown in column 5 of the spreadsheet here. Data for the 112 proxies in the AD1820 proxy […]
As a result of the migration between servers, specialized characters in old posts are now being rendered as garbage quotes. The characters that are affected are mainly “, -, ‘, …, , ü , … Each of these renders into long garbage strings. To fix the problem, one needs to do a bulk find-and-replace over […]
Judith Curry suggested that we talk a little about Mann et al 2007 available here . I noted its publication last summer when Jean S and UC made some remarks about it. It has an extensive SI with code here and, in fairness to Mann, there is a serious attempt at documenting his work in […]
The position at ClimateAudit is that error bars in MBH98 are incorrectly calculated and “pseudo science” and that no one knows how the error bars in MBH99 were calculated (not just Me, Jean S, UC but also von Storch) and these error bars are also “pseudo science”. Notwithstanding this view, UC has posted up MBH98-style […]
Loehle’s introduction emphasized the absence of tree ring chronologies as being an important aspect of his network. I think that he’s placed too much emphasis on this issue as I’ll show below. I previously noted the substantial overlap between the Loehle network and the Moberg low-frequency network. I thought that it would be an interesting […]
Climate Audit 