Tag Archives: ammann

Supplementary Information and Flaccid Peer Reviewing

Based on my limited experience, it seems to me that journal peer reviewing faces an interesting challenge with the increased use of Supplementary Information (and I absolutely endorse detailed SI and obviously encourage even more detailed SI). In a very non-random of articles that I know inside-out (Team journal publications), my conclusion is that, in […]

The MBH AD1450 Network

Most of my previous discussion of MBH pertained to the AD1400 network. In recent discussion over at Tamino, some of the posters have stated that BCPs only matter for the AD1400 network and that everything is fine for the AD1450 and later networks, relying here on statements in Wahl and Ammann 2007. (I don’t suppose […]

Where's Caspar?

As you know, we are eagerly awaiting the publication of the following article by Wahl and Ammann reported here: Wahl, E and C Ammann (In press). “Robustness of the Mann, Bradley, Hughes reconstruction of northern hemisphere surface temperatures: Examination of criticisms based on the nature and processing of proxy climate evidence.” Climatic Change (accepted). May […]

Overfitting by Inverse Regression

Wahl and Ammann 2006 reported that they could “get” something that was sort of HS-ish without principal component analysis. It wasn’t through a simple mean or CVM; it was through Mannian inverse regression. Juckes et al shows many reconstructions using “inverse regression”, mentioning in his conclusions that inverse regression caused over-concentration on a few proxies. […]

Q.e.d.

One point that Wahl and Ammann and ourselves agree on, but which Juckes appears to contest, is that principal components methodologies applied to AD1400 MBH98 networks result in upweighting or downweighting of bristlecones. Their Scenario 6 shows reconstruction results without bristlecones for covariance, correlation and Mannian PCs. I have no dispute with these calculations although […]

Wahl and Ammann Again #2

Here’s a pretty little graph that I think that you’re going to see more of. One is using the Wahl-Ammann variation of MBH methodology applied to MBH data; the others are from low-order red noise. Pink – no PC reconstruction from WA without strip-bark and Gaspé; black – from low-order red noise. I worked this […]

Wahl and Ammann Again #1

I asked KNMI what were the studies that had "refuted" our work. It seems to be Wahl and Ammann. I’ve never understood the traction of Wahl and Ammann with climate scientists. I doubt that any of them have worked through the details, but Wahl and Ammann issued a press release that all our claims were […]

Supplementary Comments to NAS Panel

We sent in the following two supplementary comments to the NAS Panel, one commenting on answers provided by Mann subsequent to our presentation and noting up points related to the revisions of Wahl and Ammann [2006] and rejection of the Ammann and Wahl submission to GRL here and the other responding to a question from […]

Letter to Climatic Change

I was asked to review the Wahl and Amman submission in May 2005 and recently posted up my review here. The first recommendation in my review was that all Wahl and Ammann remove all arguments that depended on their rejected GRL article. They didn’t and now it’s come back and should haunt them. Despite providing […]

The RE Benchmark in A&W

There’s an interesting irony in the GRL rejection of the Ammann & Wahl Comment and it will be interesting to see how this gets handled. It turns out that the A&W Climatic Change depends on their GRL submission for their test of statistical significance for the RE statistic. So even though the GRL referee thought […]