Tag Archives: RegEM

Notes on RegEM

Quiet blogging lately for a variety of reasons. In today’s post, I’m going to spend some time parsing RegEM (Truncated Total Least Squares) methodology, in itself hardly a standard technique, but particularly quirky in the Mann et al 2008 implementation. In the analysis leading up to O’Donnell et al 2010, we ported the Tapio Schneider […]

Speculating Privately

Iridge versus TTLS. What if a key text on this conundrum of the day resided in an anonymous open peer review? Would we, within the ethical standards of modern climate science, be entitled to speculate on the identity of the author of these pearls? Or would that be an ethical violation “as bad as possible”? […]

Yet another Upside Down Mann out

Science published today yet-another-Mann-et-al-reconstruction: Michael E. Mann, Zhihua Zhang, Scott Rutherford, Raymond S. Bradley, Malcolm K. Hughes, Drew Shindell, Caspar Ammann, Greg Faluvegi, and Fenbiao N: Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly, Science 326 (5957), 1256. [DOI: 10.1126/science.1177303]. Seems to me that Mann has re-discovered the Medieval […]

TTLS in a Steig Context

Many CA readers know a lot about regression and quite a bit about principal components, but I dare say that a much fewer number are familiar with Truncated Total Least Squares (to which the regpar parameter belongs.) We’re seeing interesting interactions between PC=k and regpar=r – and there is little, if anything, in regular statistical […]

Ryan O: More Mannian Algorithm Problems

Ryan O has observed a remarkable property of the Mannian algorithm used in Steig et al’s Antarctic temperature reconstruction described in a lengthy post at Jeff Id’s here and cross-posted at Anthony’s. Source code here (the source code style BTW evidencing engineering tidiness from which we should all take heed). I’m reporting here on one […]

Jeff on Steig RegEM

Jeff has made some progress on the basis that PC was applied to the AVHRR data before RegEM. See a good post here . This is obviously inconsistent with claims at realclimate.org by Gavin Schmidt and Eric Steig, but we’ve known for a while that their explanations are not accurate. This is a different exercise […]

Beckers and Rixen 2003 – Another Infilling Approach

Beckers and Rixen 2003 url is an interesting read in two respects: 1) they present a non-RegEM infilling approach. The method appears to be exactly the same as one that I (independently) implemented and illustrated about a month ago – what I termed “truncated PC”. This was actually the very first thing that I did […]

RegEM Impact on Peninsula Correlations

There has been a good deal of discussion regarding the correlation between temperatures at various locations throughout Antarctica. Several people have looked at the relationship between correlation and distance by creating graphs linking the two. IMO, one of the difficulties in interpreting these is that they are affected by a variety of factors, including the […]

Mann 2008 – Replication II

Let’s continue Mann 2008 – Replication with EIV. To run regreclow.m and regrechigh.m you’ll need files climate, eofnumb, and proxyN, where N runs from 1 to 19. I’ve run prepinputforrecon.m with required folder structure (C:\holocene\s1\zuz10\work1\temann\ etc.) in my computer. After that I did run regrechigh.m in folder C:\holocene\s1\zuz10\work1\temann\zzrecon1209\nhnhscrihad\highf and regreclow.m in folder C:\holocene\s1\zuz10\work1\temann\zzrecon1209\nhnhscrihad\lowf The regem […]

RegEM PTTLS Ported to R

I’ve now ported my emulation of Schneider’s RegEM PTTLS to R and benchmarked it against Jeff’s Matlab as shown below. I caution readers that this is just an algorithm. There are other ways of doing regressions and infills. The apparent convergence to three PCs noted by Roman is still pending as a highly interesting phenomenon. […]

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