Comments on: A Cook's Tour

By: The Trouet Ocean Proxies « Climate Audit

The Trouet Ocean Proxies « Climate Audit — Sat, 11 Sep 2010 15:34:39 +0000

[...] of an RE statistic – an untrue claim, since Cook claimed verification RE and CE as well. Also here in connection with replication issues, but I haven’t considered recently. I’ve [...]

By: Steve Sadlov

Steve Sadlov — Tue, 14 Nov 2006 16:33:05 +0000

RE: #7 – SPAMBOT ALERT! SPAMBOT ALERT!

By: TCO

TCO — Sat, 27 Aug 2005 04:20:48 +0000

1. Meaning based on situations where the drought or temperature was independantly measured? So what were the differences in correlation coefficient or rsq?

2. One way to deal with this is to urge additional field studies. One is to try to get the data unlocked. What’s your vote?

3. So is this kind of baseline work done to allow the proxy work itself? What is it’s quality. If I would think one could do some pretty decent measurements and even controlled experiments here.

4. So the response is U-shaped, do the proxy guys refer to this and then use a “U-transform” to extract the implication? Do they take efforts to deconfound the effects of other variables (rain etc.), perhaps by referring to studies done on rain sensative species?

By: Steve McIntyre

Steve McIntyre — Sat, 27 Aug 2005 04:05:48 +0000

1) As I recall, about half the trees in the MBH dataset as temperature indicators also occur in this dataset as drought indicators. Lots of tree rings correlate better with drought than temperature. The question was what they were doing in the MBH network in the first place.

2) The post-1980 data hasn’t been integrated and much of it isn’t archived. Jacoby has done nearly 100 North American series since 1990 and (I’m pretty sure has) archived only one. I don’t think that Esper has archived anything. Hughes has not archived any bristlecone updates. I feel certain that, if the Sheep Mountain bristlecone samples taken in 2002, were showing off the charts results, then we’d have heard about it.

3) I think that botanists are a long way away from being able to predict tree rings or even make a good stochastic model. However, there’s solid evidence that conifers have an upside-down U (quadratic) response to temperature in botanical studies; it’s only dendrochronologists that try to distort this into a linear relationship to temperature.

By: TCO

TCO — Sat, 27 Aug 2005 03:50:30 +0000

1. How does this post (or the article or research) show that drought correlates better with trees than temp?

2. You state that much data does run past 1980. Do you no longer feel additional feild studies are warranted?

3. To what extent has careful observation (or even direct experimentation) on trees been able to determine the multiple regression style response equation to sun, temp, rain, etc. etc? It would seem possible to do this type of experiment and get some really good intutions to baseline what mean and SD of tree ring size or density or whatever is expected. Is this baseline setting work well done and agreed on?

By: Murray Duffin

Murray Duffin — Wed, 20 Jul 2005 22:44:43 +0000

Have you looked into the possibility of getting a couple of college students to do detail projects for you? It is clear that you need some way to augment what you can do yourself. Every time you turn over another rock a whole lot of anomalies crawl out. I surely admire your one man effort and productivity, but you now clearly need help to pursue the several interesting trails you have identified. I wish I could help, but I know almost nothing of statistics. Murray

By: Murray Duffin

Murray Duffin — Fri, 15 Jul 2005 14:02:40 +0000

Steve, when do you expect to return to this topic. It seems like it could be a quite critical indicator. in the graphs above I’m surprised that the dark curve in the upper, long term graph doesn’t show a higher peak near 1940, corresponding to the detailed lower curve. Is this some artifact of the way smoothing was done? I am betting that if you can push the dendrochronology out 15 years, to about 1995, it will agree with the curve where you tacked the satellite record onto Moburg. Murray

Steve: Nice of you to ask. It’s rather fallen off my radar screen. I really feel overwhelmed right now with topics. I also need to finish some journal articles. butI appreciate the reminder and thought. steve

By: Michael Ballantine

Michael Ballantine — Thu, 17 Mar 2005 05:20:49 +0000

Sounds like Cook, Mann or both of them picked the wrong sites. What happens to their respective reports if all overlapping sites are discarded?
And one small nit to pick, the last graph wipes out most of the last sentance. At least in Safari.