Tag Archives: Yamal

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 […]

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 […]


Naurzbaev et al [2004] is a terrific article by Naurzbaev, Hughes (yes, that Hughes) and Vaganov about deducing climate information from tree-ring growth curves in Siberia. (I find Naurzbaev’s work consistently interesting.) They studied 34 larch sites in a meridional transect from 55 to 72 N (at a longitude of about 90-100E) and 23 larch […]