from: "Wahl, Eugene R" <wahleatXYZxyzred.edu>
subject: RE: confidential
to: "Keith Briffa" <k.briffaatXYZxyz.ac.uk>
I hope you are well in all this!!
I have done my best this evening to digest the issues you asked me to look at, and to give perspective on them. Here is what I can offer at this point.
1) Thoughts and perspective concerning the reviewer's comments per se. These are coded in blue and are in the "Notes" column between pages 103 and 122 inclusive. It got to the point that I could not be exhaustive, given the very lengthy set of review thoughts, so I am also attaching a review article Caspar and I plan to submit to Climatic Change in the next few days. [The idea is that this would accompany the Wahl-Ammann article, to summarize and amplify on it -- given all the proper and non-proper interpretation WA has received and the need for subsequent analysis that WA only lightly touches on. Steve Schneider is aware that it is coming.] I think a read through this, especially the part on PCs and Bristlecones, can say about all I might offer additionally. It is not lengthy.
Please note that this Ammann-Wahl text is sent strictly confidentially -- it should not be cited or mentioned in any form, and MUST not be transmitted without permission. However, I am more than happy to send it for your use, because it succinctly summarizes what we have found on all the issues that have come up re: MBH. As you can see, we agree at some level with some of the criticisms raised by MM and others, but we do not find that they invalidate MBH in any substantial way.
2) I have added a brief suggested alteration to page 6-3 of the draft text you sent, to take into account the fact Wahl-Ammann decidely settles the issue concerning how proxy PC calculations impact the MBH style reconstruction. These changes are encoded using WORD's "Track Changes" feature.
I did not get into suggesting how that paragraph might otherwise be rewritten. You can see more generally where Caspar and I have gone in the attached text, and how our work relates generally to the MM, von Storch, etc. "examinations" of MBH. Thinking further, the "Validation Thresholds and Measures of Merit" and "Amplitude Issues" sections might also be well worth a look. The former will help you see how over-strong and one-sided are the arguments Steven McIntyre puts forth in this area. (Cf. Wahl-Ammann Appendix 1 also on this topic -- McIntyre strongly avoids, or simply chastizes as ad hoc, the false negative issues at lower frequencies that we raise concerning the use of r2.) He has done with the IPCC just what he did in reviewing the Wahl-Ammann paper--and indeed in all his efforts--write volumes of very strongly worded, one-sided critiques, which can take a lot of time to see through and then respond to. I hope what we have written can help you in this way. I note that Mike Mann, Richard Alley, and others have written response comments, which would be useful for getting perspective also.
Finally, note also that I corrected the reference to Wahl, Ritson, Ammann (Wahl et al., 2006) on page 6-6, and put the correct publication information in the reference section.
I hope this all helps. I would be happy to do my best to answer any further questions you might have.
All the best, and Peace, Gene
Dr. Eugene R. Wahl
Asst. Professor of Environmental Studies
1 Saxon Drive
Alfred, NY 14802
From: Keith Briffa [mailto:email@example.com]
Sent: Tue 7/18/2006 10:20 AM
To: Wahl, Eugene R
I am taking the liberty (confidentially) to send you a copy of the
reviewers comments (please keep these to yourself) of the last IPCC
draft chapter. I am concerned that I am not as objective as perhaps I
should be and would appreciate your take on the comments from number
6-737 onwards , that relate to your reassessment of the Mann et al
work. I have to consider whether the current text is fair or whether
I should change things in the light of the sceptic comments. In
practise this brief version has evolved and there is little scope for
additional text , but I must put on record responses to these
comments - any confidential help , opinions are appreciated . I have
only days now to complete this revision and response.
note that the sub heading 6.6 the last 2000 years
is page 27 line35 on the original (commented) draft.
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Attachment Converted: "c:\eudora\attach\AW_Editorial_July15.doc"
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Attachment Converted: "c:\eudora\attach\Ch06_SOD_Text_TSU_FINAL_2000_12jul06_ERW_suggestions.doc"