date: Wed, 05 Nov 2003 07:53:15 -0500
from: "Michael E. Mann" <mann@virginia.edu>
subject: ad additional suggestion...
to: Scott Rutherford <srutherford@rwu.edu>, "Raymond s.bradley" <rbradley@geo.umass.edu>, mhughes@ltrr.arizona.edu, Tim Osborn <t.osborn@uea.ac.uk>, "Keith Briffa" <k.briffa@uea.ac.uk>, Phil Jones <p.jones@uea.ac.uk>, mann@virginia.edu

   Dear All,
   Hopefully, the JGR paper on which Scott is first author and we're all co-authors, should be
   coming back from review soon (Scott--please contact J. Climate to find out what the status
   is ASAP). As I mentioned before, I see this as a natural first step in the broader future
   collaborative effort that Keith has nicely layed out, in which we can look in detail at the
   sensitivity to selection of candidate predictors, issues of seasonal, spatial sampling,
   etc---all of the things we all know need to be looked at in more detail.
   I strongly endorse the idea of making this a collaborative effort of the full group of us,
   perhaps w/ Tim and Scott in the lead of the joint project (do people feel this is
   reasonable?). Between the two groups, I think we're fully funded for this type of
   activity...
   Along these lines, I have a suggestion for Scott regarding the J. Climate paper that should
   be coming in from review soon. A few important measures taken here can go a long way to
   combatting the latest E&E criticism of MBH98, since we get essentially the same results for
   the MBH98 network w/ a completely different statistical method, and explicitly compare
   results w/ other networks, etc.
   By the time the paper appears, we want to have a supplementary website (to which we should
   plan to refer in the paper!) that will have *all* data, and *all* codes (Scott's MATLAB
   codes--clean these up first though Scott) used, and a *thorough* description of all
   methodological details (no matter how small) so that independent scientists would have
   everything they need to reproduce the results. We're not all in the habit of doing this,
   and its now clear that, in certain cases, we need to...
   I also have one other suggestion--Scott, you should go through the MBH98 dataset (refer to
   the original description to determine where the termination dates were) and make sure that
   any extensions beyond the last available data point by persistence that I performed
   originally are removed--we don't need them, since RegEM can handle the missing data in
   estimating the required covariances anyway!  You should also do an experiment where the
   MBH98 network is only used in calibration through 1971 (the earliest date for which no
   series have been extended to the 1980 boundary by persistence), since the "PC" predictor
   series are already based on some data that have been extended, and its not worth the bother
   to redo these all. Stopping the calibration in 1971 is another way of avoiding the use of
   any persistence-extended data...
   In our reply to MM03, I'll be showing that we get a virtually identical result if we only
   use a 1902-1971, rather than 1902-1980, training period, taking away from MM03 the argument
   that the extension of some series by persistence to 1980 makes any difference.
   If we do all of the above for the in-review Rutherford et al J. Climate paper, and have the
   website up and running (perhaps working w/ Mark Eakin at NGDC to have the webpage located
   there to, or at  least a link to our webpage), we take away a  major source of criticism.
   Thoughts?
   mike

   ______________________________________________________________
                       Professor Michael E. Mann
              Department of Environmental Sciences, Clark Hall
                         University of Virginia
                        Charlottesville, VA 22903
   _______________________________________________________________________
   e-mail: mann@virginia.edu   Phone: (434) 924-7770   FAX: (434) 982-2137
            [1]http://www.evsc.virginia.edu/faculty/people/mann.shtml

