Tag Archives: rahmstorf

Rahmstorf’s Third Trick

Rahmstorf et al 2015 Figure 5 shows a coral d15N series from offshore Nova Scotia (see left panel below). The corresponding plot from the source is shown on the right.  Original captions for both follow.  There’s enough information in the figures and captions to figure out Rahmstorf’s next trick. See if you can figure it out […]

Rahmstorf’s Second Trick

The Rahmstorf et al reconstruction commences in AD900 even though the Mann et al 2009 reconstruction goes back to AD500.  Once again, this raises the obvious question: why didn’t Rahmstorf show values before AD900?  Are these results adverse to his claims? Once the question is posed, you can guess the answer. 

Rahmstorf’s First Trick

In any article by Mann and coauthors, it is always prudent to assume that even seemingly innocent choices use up a researcher degree of freedom – to put it nicely. For example, Rahmstorf et al focus on their “AMOC index” in the period ending 1995 and show their AMOC index up to as shown below.

Reductio ad mannium

The new article by Rahmstorf and Mann (see RC here) has been criticized at WUWT (here here) for making claims about Atlantic Ocean currents based on proxies, rather than measurements. (Also at Judy’s here)   But it’s worse, much worse than we thought. Rahmstorf and Mann’s results are not based on proxies for Atlantic current velocity, but […]

Rahmstorf Rejects IPCC Procedure

Over the past few days, we’ve discussed many peculiar aspects of Rahmstorf smoothing and centering: incorrect disclosure; seeming unawareness of what the smoothing did; unattractive properties of the triangular filter; the enhancement of “successful” prediction; opportunistic policy changes. It’s not though IPCC hadn’t turned its mind to smoothing. IPCC AR4 enunciated a sensible policy on […]

Rahm-Centering: Enhancing "Successful" Prediction

I only have time to post a quick note on this interesting aspect of Rahmstorf’s diagram – how the centering of Rahmstorf et al 2007 interacts with Rahm-smoothing (now conceded by everyone except Rahmstorf to be a simple triangular filter of 2M-1 years) to enhance “successful” prediction. I noticed this effect when I did a […]

The Secret of the Rahmstorf "Non-Linear Trend Line"

Since the publication of Rahmstorf et al 2007, a highly influential comparison of models to observations, David Stockwell has made a concerted effort to figure out how Rahmstorf smoothing worked. I now have a copy of the program and have worked through the linear algebra. It turns out that Rahmstorf has pulled an elaborate practical […]

Rahmsmoothing and the Canadian GCM

Quite aside from the realclimatescientistsmoothingalgorithmparameterselectioncontroversy, another interesting aspect of Figure 3 of the Copnhagen Synthesis Report is the cone of model projections. Today I’ll show you how to do a similar comparison for an AR4 model of your choice. Unlike Rahmstorf, I’ll show how this is done, complete with turnkey code. I realize that this […]