You’ll probably have more luck than me. (They completely stonewall me.)

At the time, I was interested in the series primarily because of its extraordinary impact on MBH98 results. It was the ONLY series (out of over 400) which Mann extrapolated at the beginning. He did this to get it into his 15th century reconstruction, where it brought down the 15th century result significantly. I was criticla of the extrapolation, the quality of the 15h century portion (1 tree for many years), the invalidity of the cedars as temperature proxy, the failure to disclose the extrapolation, the misrepresentation of the start date of the series in the article so that no one (without crosschecking as I did against original data) would have known about the unique extrapolation.

This series and the bristlecones are what drive MBH98 in the 15th century reconstruction.

The y-axis is dimensionless units in a usual chronology (1 instead of 1000). I’m 99.99% sure that the pink series was created using ARSTAN with negative exponential options. I’ve replicated this calculation as a check on some of the software that I’ve written in R to do site chronologies (I’ve experimented a lot on this)- actually there are some interesting numerical results.

The convergence of negative exponentials is sensitive to parameters in the numerical methodology. Using ARSTAN, 16 of 29 series converge (with 12 modeling as mean and one a negatively sloped line). If you change the numerical convergence parameters, I could get 27 of 29 to converge. There is a really odd error in ARSTAN whereby the parameters for the first series are always wrong. I have no idea why.

to answer a question like that it would be necessary to how many trees contributed to each curve. by the way is this data detrended? or is the y axis mm?

The Jacoby data is not archived. (He’s archived virtually no North American data taken after 1991.) It was a bit accidental that I came into possession of this graphic. I requested a copy of the measurement data unsuccessfully. When I tried to find out further information about the new version, they got all shirty and said that I should look at the old data as it was more "temperature sensitive". If you go to the right bar category -Jacoby, you will see some of my frustrating efforts with Jacoby.

Ross McKitrick and I met with cedar specialists at the University of Guelph (Larson, Kelly) who were very dubious (to say the least) about whether cedars could be used as a temperature proxy. They’ve studied hundreds of cedars for over a decade and said that they like cool moist conditions – an upside-down U.

As to checking site conditions, I asked JAcoby for the location of the Gaspe site. He said that they did not know whether the original trees were sampled as it was done pre-GPS (unconvincing to someone who’s worked with geologists) and wouldn’t say where the second sample was taken place. I was going to get someone to check the site. Pretty frustrating. Cheers, Steve

Please stop publishing anything meaningful in EE. Put your stuff in the real journals. There are enough of them that you can still be in the regular abstracted, looked at by the field, journals; even if you are blackballed a bit by the hockeyteam from Nature or even GRL (at times).

the blue line might well be individual trees which show growth reduction because of moisture stress or other factors. should be relatively easy to check.

how many trees are in each chronology? it might well be that averaging all trees at that site is not the proper method to extract climate information for neither the “old” series, pink, nor the “new” series, blue.

This is Talos Dome on Antarctica data 1200 – 1996. Almost suitable as cue for pool?

Reference:
Stenni, B, et al 2002, Eight centuries of volcanic signal and
climate change at Talos Dome (East Antarctica),
Journal of Geophysical Research,
vol, 107, no, D9, 10,1029/2000JD000317,