Category Archives: Statistics

Brown and Sundberg: "Confidence and conflict in multivariate calibration" #1

Introduction If one is to advance in the statistical analysis of temperature reconstructions, let alone climate reconstructions – and let’s take improving the quality of the data as the obvious priority – Task One in my opinion is to place the ad hoc Team procedures used in reconstructions in a statistical framework known off the […]

Calibration in the Mann et al 2007 Network Revisited

In a post a few months ago, I discussed MBH99 proxies (and similar points will doubtless apply to the other overlapping series) from the point of view of the elementary calibration diagram of Draper and Smith 1981 (page 49), an older version of a standard text. Nothing exotic. One of the problems that arose in […]

Koutsoyiannis 2008 Presentation

Anything by Demetris Koutsoyiannis is always worth spending time on. Spence_UK draws our attention to this recent presentation at AGU asking: How well do the models capture the scaling behaviour of the real climate, by assessing standard deviation at different scales. (Albeit at a regional, rather than global level). Assessment of the reliability of climate […]

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 […]

PC Weights on a Square Region

A few days ago, I showed some plots showing distribution of weights arising from principal components carried out on data from a region arranged as a line segment (think Chile). Today I’ve done a similar analysis for a square shaped region again assuming spatial autocorrelation governed by distance. In this case, I made a regular […]

Toeplitz Matrices and the Stahle Tree Ring Network

One of the most ridiculous aspects and most misleading aspects of MBH (and efforts to rehabilitate it) is the assumption that principal components applied to geographically heterogeneous networks necessarily yield time series of climatic interest. Preisendorfer (and others) state explicitly that principal components should be used as an exploratory method – and disavowed any notion […]

Data Smoothing and Spurious Correlation

Allan Macrae has posted an interesting study at ICECAP. In the study he argues that the changes in temperature (tropospheric and surface) precede the changes in atmospheric CO2 by nine months. Thus, he says, CO2 cannot be the source of the changes in temperature, because it follows those changes. Being a curious and generally disbelieving […]

Re-Visiting RegEM: Rutherford et al 2005

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 […]

Emile-Geay and Verification r2 Statistics

Julien Emile-Geay from Judith Curry’s university – who, together with Kim Cobb, is teaching a course on the Hockey Stick – has joined our debate with a forceful criticism of Craig Loehle’s recent paper. While Emile-Geay seems to be a lively young man with some very cordial comments about CA here and his comments are […]

What other data series could be plugged in?

I recommend that CA readers visit UC’s blog for some interesting discussion. (BTW UC visited Toronto recently and we had a nice dinner.) UC posted the following interesting figure on Unthreaded as follows: BTW, got interesting result when I replaced Temperature PCs with solar in MBH98 algorithm. Similar RE values as in the original, and […]