Category Archives: Yamal and Urals

Response to Briffa #2

As noted at CA last week, Briffa published a partial response to Yamal issues at the CRU website, one post discussing the impact of the Yamal chronology in various studies and another post discussing the Yamal chronology itself. For a response to Briffa’s online article on the impact of Yamal, I refer readers to last […]

Briffa on Yamal Impact

Keith Briffa has a couple of posts today on Yamal – one discussing its impact in other multiproxy studies and the other on the Yamal chronology itself. His post on the Yamal chronology includes a careful consideration of various issues involved in the development of the Yamal chronology and is accompanied by an extensive archive […]

RCS – One Size Fits All

In examining the Briffa Yamal chronology, there has been a lot of emphasis (IMHO, correctly) placed on both the cherry-picking and the low core counts of the proxies which extend into recent times. However, the chronology also depends on the various methods used to adjust for various known biological effects and on the choices for […]

Re-Visiting the "Yamal Substitution"

Reader Tom P observed: If Steve really wants to invalidate the Yamal chronology, he would have to find another set of cores that also gave good correlation with the instrument record, but indicated a previous climate comparable or warmer than that seen today. As bender observed, Tom P’s question here is a bit of a […]

The NAS Panel and Polar Urals

Now that we know the abysmally low replication of the modern portion of Briffa’s Yamal chronology (something previously unknown to specialists), I’ve been backtracking through some earlier documents to see how this may have impacted past studies. We’ve talked previously about how Briffa refused to provide measurement data to D’Arrigo et al 2006, resulting in […]

Core Counts and Reverse Engineering

Recently, after the posting of the Phil Trans B archive on Sept 8, 2009, I determined that the Yamal data set as used by Briffa is not more “highly replicated” than the Polar Urals data set and thus there is no basis for the preferential selection of the Yamal chronology over the Polar Urals chronology […]

Yamal and the Divergence Problem

One of the aspects of the Yamal discussion that is perhaps clearer to regular CA readers than to new readers is that Briffa’s Yamal chronology was very different from ring width chronologies previously reported in the area (including by Briffa itself.) Shortly after the publication of Osborn and Briffa 2006 and D’Arrigo et al 2006 […]

Yamal and IPCC AR4 Review Comments

I was one of the more industrious reviewers for IPCC AR4. In my Review Comments, I made frequent reference to Yamal versus the Polar Urals Update, expressing concern about the rationale for using Yamal rather than Polar Urals, an issue that is once again in play. Keith Briffa was the section author and can be […]

Gavin's Guru and RCS Standardization

Obviously, there has been considerable controversy over the past few days over the Yamal data. First, let’s observe the continued silence of field dendros on the dispute. None have stepped forward so far to support Briffa’s use of 10 cores in 1990 (and 5 in 1995). As others have observed, their silence is rapidly becoming […]

Keith Briffa Responds

In spite of suffering a serious illness (which I understand to be a kidney problem), Keith Briffa has taken the time to comment on the Yamal situation. The comment should be read by interested readers. If Briffa or any of his associates wishes to post a thread here without any editorial control on my part, […]

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