Tag Archives: briffa_2000

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 […]

Fresh Data on Briffa’s Yamal #1

A few days ago, I became aware that the long-sought Yamal measurement data url had materialized at Briffa’s website – after many years of effort on my part and nearly 10 years after its original use in Briffa (2000).

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: […]

Rob Wilson and the Yamal Divergence

The archived information for Wilson et al 2007 contains interesting new information on an unpublished West Siberian series (Putorama, 70 31 N, 92 57E). In this case, I was actually able to obtain a better correlation to gridcell temperature than the one reported by Rob by using a gridcell closer to the actual location. This […]

Briffa 2000 and Yamal

If you actually look at the medieval proxy index of the "other" studies (Briffa 2000, Crowley and Lowery 2000, Esper et al 2002, Moberg et al 2005), the medieval proxy index is usually just a razor’s edge less than modern proxy index – just enough that the study can proclaim with relief that the modern […]

Briffa vs Esper #2

People have been wondering why there is such difference between Polar Urals versions. In many cases, the archived Osborn and Briffa [2006] version (smoothed) is consistent with the emailed Esper et al [2002] version – but not always. It’s always worthwhile examining differences and here are a few.

Polar Urals: Briffa versus Esper

It’s interesting that the Hockey Team seems to be able to make spaghetti graphs of world temperature history when they can’t even arrive at a spaghetti graph for the Polar Urals. I posted up the difference between Briffa’s Yamal substitution and the updated Polar Urals ring widths. But before either one, there was Briffa’s Polar […]

Wilson on Yamal Substitution

Rob Wilson has written in sharply criticizing me (Yamal Substitution #3) for a lack of a balanced presentation on the Yamal substitution, and, in particular, for not acknowledging the "clear statistical reasons (related to variance changes through time)" that he had provided me offline for why D’Arrigo et al 2006 made the Yamal substitution. Also […]

Yamal Substitution #3

There’s some very important new information related to the “Yamal Substitution” – which sounds like a Ludlum novel title – in the Esper site chronologies which Science provided today. Also see here here here. Here’s a plot of a 40-year smooth of the Esper site chronology for Polar Urals and Briffa’s archived version of the […]

More on the Yamal Substitution

I wrote recently about the Yamal substitution for the Polar Urals series in both Osborn and Briffa [2006] and D’Arrigo et al, 2006. This substitution is not incidental as the Yamal version had by far the strongest closing uptick in either data set, while the updated Polar Urals ring width series (1998 update) had elevated […]

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