Category Archives: Jones et al 1998

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 […]

Jones et al [1998]: Verifying Reported Gridcell Correlations

Jones et al. [1998] makes the reasonable policy that proxies should be validated against gridcell temperatures as evidence that they are temperature proxies, noting that this is not always done. This policy is endorsed in Jones and Mann [2004], who note that not all multiproxy studies had observed this policy, presumably including MBH98, which included […]

Jones et al [1998]: Variance Adjustment

The first step in the J98 procedure is the standardization of all series based on 1901-1950 and then taking an average. I’m not a big fan of short-period standard deviations (not just me, but see also Trenberth [1984]). All of these series are at least 300 years long, so there’s no need for 50-year standard […]

Jones et al. [1998]: The Proxies

Jones et al [1998]] did not archive their proxy set as used. I requested this information from Jones this year and was refused, although he did send me two series (Lenca, Law Dome) not locatable anywhere in a public archive about a year ago. Here is some background on the proxies in Jones et al […]

Jones et al [1998]: Confidence Intervals

I’m working away at Jones et al [1998]. Here’s an interesting diagram from Jones et al [Science, 2001] , which purports to provide confidence intervals for the J98 reconstruction (blue). There’s (at least) one really strange feature in this diagram. See if you can pick it out. Original Caption: Fig. 2. (A) Northern Hemisphere surface […]

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 […]

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 […]

Noise in Multiproxy Studies

Someone asked what the graphs in Noise in Jones 1998 would look like for the other multiproxy studies. I speculated that they would probably look similar. In fact, they vary quite a bit. I’ve done plots for Mann and Jones [2003], Esper et al [2002], Crowley and Lowery [2000], Moberg et al [2005] and MBH99. […]

Noise in Jones et al [1998]

People often have a hard time grasping how dificult it is to statistically distinguish between the vaunted multiproxy studies and red noise. Here are a few interesting images from the Jones et al [1998] proxy roster, which I’ve been working on.

Jones et al [1998]: Gridcell Correlations

Since I showed the effect of smoothing on the relationship of Dunde to temperature, I thought that it would be useful to post up a table showing the Jones et al [1998] proxy correlations to temperature versus my calculations using HadCRU2.

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