Tag Archives: urals

What Happened to Polar Urals?

Addiction of paleoclimate reconstructions to particular proxies has been a longstanding concern at Climate Audit. One of the battleground issues has been the addiction to Briffa’s Yamal tree ring series, while the nearby update of Polar Urals (with a pronounced MWP) was disappeared. (See CA category.) Just before Climategate, we raised questions about the Yamal […]

Difference in Yamal Versions “Not Insignificant”

In July 2003, Tim Osborn advised Tom Crowley that there were multiple versions of Yamal (and Tornetrask) and that he needed to contact Briffa prior to using: The other files are “tornad.rcs” and “yamal.rcs” which are RCS-standardised tree-ring width series. I would really strongly suggest that you contact Keith Briffa about exactly what these series […]

Core Count in Phil Trans B

The Yamal reconstruction was introduced in Briffa 2000, a survey paper that did not include elementary information like core counts. As a result, users of the Briffa 2000 Yamal reconstruction (including Mann and Jones 2003, Moberg 2005, Hegerl 2007; D’Arrigo 2006, IPCC 2007, etc…) used it without any knowledge that the core counts did not […]

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 […]

Esper et al 2009 on West Siberia

Esper et al (Global Change Biology, in press) “Trends and uncertainties in Siberian indicators of 20th century warming” is relevant to our present consideration of Briffa’s Yamal, which I will get to shortly. The cutline in their abstract declares in effect that the divergence problem is not as “bad as we thought”: Despite these large […]

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 […]

Updating Briffa 2000

Briffa 2000 is one of the canonical “independent” reconstructions in the IPCC AR4 spaghetti graph, the Wikipedia spaghetti graph and similars. I’ve discussed it in the past, but I’m going to revisit this in light of the new information on Tornetrask and I’m going to run Brown’s inconsistency statistic on it. Briffa used 7 series: […]

Jones et al 1998: Impact of New Versions

We keeping hearing the incantation from the Team that all the reconstructions on the Jesuit Index show a warmer modern than medieval period. I reported that I recently obtained a digital version of Grudd’s revised Tornetrask reconstruction and I’ve been anxious to test out its impact on the Jones et al 1998 reconstruction (together with […]

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