Category Archives: Source Code

Code: The Hockey Stick

%%%% Matlab version of Hockey Stick % %Mann, M. E., R. S. Bradley, and M. K. Hughes (1998), Global-scale %temperature patterns and climate forcing over the past six centuries, %Nature, 392, 779– 787. % %Mann, M. E., R. S. Bradley, and M. K. Hughes (1999), Northern %Hemisphere temperatures during the past millennium: Inferences, uncertainties, %and […]

An Example of MBH "Robustness"

In the MBH source code, they apply steps that purport to weight the temperature PCs in their regression calculations proportional to their eigenvalues. Comments on their code say: c set specified weights on data … c weights on PCs are proportional to their singular values This is one of two weighting procedures in MBH for […]

Squared Weights in MBH98

A couple of weeks ago, I said that I would document (at least for Jean S and UC) an observation about the use of squared weights in MBH98. I realize that most readers won’t be fascinated with this particular exposition, but indulge us a little since this sort of entry is actually a very useful […]

Mann's co2detrend.f Calculation

If someone felt that it was necessary to detrend the bristlecone pine-based PC1 of Mann’s AD1000 network for CO2 fertilization, it’s doubtful that the initial instinct would be to coerce the data to a network of northern Canadian-Alaskan tree ring chronologies where the possibility of regional differences must surely be allowed for. Inspection of Mann’s […]

More Linear Algebra

I’m not sure that there’s a huge demand for more linear algebra on MBH98, but here’s the rest of the proof that the NH temperature index in an MBH98-type calculation is simply a linear combination of proxies and, when only one temperature PC is reconstructed, the weights are proportional to the correlation between each proxy […]

MBH Calibration-Estimation Procedure

What I’m going to show here is that the MBH98 method can be reduced to a few lines of code and, in doing so, show some other interesting results as well. Today I’m just going to get to the reconstructed temperature PCs, but I’ll show that these are linear in the proxies and later show […]

Rutherford et al [2005] Collation Errors

I’ve got something that’s a little bit amusing today. In MM03, we pointed out collation errors in pcproxy.txt (which I’ve recently hypothesized was used in the version of Rutherford, Mann et al [2005] submitted in July 2003 and was laundered after MM03). We pointed out that the PC series all seemed to start one year […]

Source Code: Preisendorfer’s Rule N

Here’s a comment on handling of Preisendorfer’s Rule N in the code dump; I’ll post some further comments on Preisendorfer on Preisendorfer’s Rule N in a few days. There is NO source code showing the application of Preisendorfer’s Rule N to tree ring networks – a battleground issue, if you will. There is some source […]

MBH98 Source Code: Status Report

I reported recently on that the recently archived (July 2005) source code multiproxy.f shows that the cross-validation R2 statistic was calculated and not reported. Today, I’m merely going to summarize some collation details from my inspection of the code, listing input files, output files and providing a lexicon of variables. The source code requires a […]

Cross-Validation R2 Source Code Reference

Just for reference: here’s the code excerpt where Mann calculates the cross-validation R2 statistics and then writes it to file. You can see the original code at ftp://holocene.evsc.virginia.edu/pub/MANNETAL98/METHODS/multiproxy.f.{Update – http://www.meteo.psu.edu/holocene/public_html/shared/research/MANNETAL98/METHODS/multiproxy.f ] Search down using corrnhem or verif1,out. There is no "if" as to whether he calculated the cross-validation R2 statistic.

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