Tag Archives: mann_2008

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 […]

Dirty Laundry II: Contaminated Sediments

From time to time, scientists inadvertently use contaminated data and their results are affected. For example, some time after publication of Grand et al (PNAS 2004), the authors determined that their results were erroneous as a “result of contamination of genomic DNA with plasmid DNA”. They promptly issued a retraction, expressing their regret for 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 […]

Mannian CPS

As a technique, CPS is little more than averaging and shouldn’t take more than a few lines of code. You standardize the network – one line; take an average – one more line; and then re-scale to match the mean and standard deviation of your target – one more line. (I’m not commenting here on […]

More on the Gridded MXD Data

We’ve noted that Briffa’s gridded MXD has high correlations to temperature, much higher than run-of-mill proxies. We’ve also noted that Mann (like Briffa) truncated this data at 1960 because of divergence. At the time that Mann et al 2008, the gridded MXD data was not available anywhere – Mann cited a webpage as follows: The […]

More on the MXD Data Set

On Sep 9, 2008, I sent an FOI request to the University of East Anglia, requesting a copy of the MXD data set as provided to Mann et al. Today (Oct 2, 2008), I was notified that they would provide this data and, sure enough the data is now posted (Oct 2, 2008) at http://www.cru.uea.ac.uk/~timo/datapages/mxdtrw.htm […]

Mann 2008: the Briffa MXD Network

Those who forget the past are condemned to repeat it. The SI for MBH (and Mann et al 2007) had incorrect geographic locations for numerous proxies. The same error is repeated in Mann et al 2008, a defect encountered by Jeff Id and myself in trying to replicate reported correlations to gridcell temperatures. Nearly 100 […]

Proxy Screening by Correlation

I’ve made histograms of reported proxy correlations for 1850-1995, as reported in r1209.xls (which contains results for all proxies, unlike SI SD1.xls which withholds results below a benchmark.) The breaks are in 0.1 intervals. On the left is the histogram before screening; on the right, a histogram of the 484 proxies after screening.     […]

MWP Non-Dendro Proxies #2

OK, I’m starting to get the feel of the new proxy network and have some ideas of what the new Mannomatic is doing. The manouevres have a lot of similarities to the moves in MBH98 and I think that a few main components can be singled out: 1. Once again, as in MBH98-99, the “proxies”, […]

Mann 2008 Non-Dendro MWP Proxies

Once again, Mann has claimed that he can obtain a “reliable long-term record” without tree ring data, a claim that, as previously noted, is eerily reminiscent of a similar untrue claim made 10 years ago. Ten years ago, we could not simply eliminate all the tree-ring data from our network because we did not have […]

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