Tag Archives: urals

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 Spaghetti Graph

I’ve got to get back to the NAS presentation and this will be my last post on Polar Urals and Yamal for a while, but it is all quite delicious. Anyway, here is a spaghetti graph of 3 Polar Urals results – including the results from Esper et al [2002] just disclosed by Science, all […]

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 […]

Polar Urals “Grass Plot”

Here’s another look at Polar Urals using a “grass plot” showing cumulative ring width for individual trees against time. The trees plotted in black are from the original archive (russ021) and the ones plotted in red are form the 1998 update (russ176). This gives a little different viewpoint on variance stabilization issues. First, one of […]

More on Urals and Tornetrask

I’m finally trying to finalize my presentation on Jones et al [1998] for the US GCRP workshop in November, which is necessarily mostly about the Polar Urals and Tornetrask reconstructions. Bot MXD chronologies and RW chronologies are supposed to correlate to temperature. So an obvious quesiton is how do they correlate to eachother. I’ve plotted […]


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 […]

Updated Polar Urals Data

I have obviously been very critical of the 11th century portion of the Polar Urals dataset used in Briffa et al. [1995], without which Jones et al [1998] does not have a cold 11th century (and which is a staple of other studies). It turns out that Schweingruber collected new subfossil samples for this site […]

Plots of Gaspe and Polar Urals Data

Just as an experiment, I plotted up all the ring widths for the Gaspé and Polar Urals sites, with each core displaced a little. What I was thinking of the type of graph that you see in seismic surveys. The look is interesting, given how much weight is placed downstream on these data sets in […]

Polar Urals: Shiyatov’s Finnish Academy Article

I’ve written on a number of occasions on Briffa’s Polar Urals reconstruction, which is used in nearly every multiproxy reconstruction, no doubt because of its uniquely cold MWP. It’s one of the key series in Crowley and Lowery [2000] and Jones et al [1998]; it’s not as important in MBH98-99 (which is more or less […]

Polar Urals #4: “Heartrot Bias”?

There appear to be some important sampling differences between subfossil and modern (living) cores. Briffa et al [CD 1992, 114] provide the following caveat with respect to using the RCS method (global curve fitting) for Tornetrask: “In applying this [RCS] method, each individual tree ring series should ideally start with the innermost ring (preferably near […]


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