cc: Scott Rutherford <srutherford@rwu.edu>, mann@virginia.edu
date: Mon, 19 Jan 2004 15:59:36 -0500
from: "Michael E. Mann" <mann@virginia.edu>
subject: Re: J. Climate paper - in confidence
to: "Malcolm Hughes" <mhughes@ltrr.arizona.edu>, "Malcolm Hughes" <mhughes@ltrr.arizona.edu>, Tim Osborn <t.osborn@uea.ac.uk>, Briffa Keith <k.briffa@uea.ac.uk>

   Malcolm,
   series (5) is 'trd.dat', a Bradley & Jones (93) series.   BJ93 was of course the nucleus of
   the MBH98 network, which was constructed by adding other indicators to that initial
   dataset. Of course, that does imply some redundancy, since many of the BJ93 series were
   composites of other data, etc. I might have gotten the reference from BJ93 for trd.dat
   wrong (Fritts and Shao is for correct for trw.dat, but perhaps not trd.dat, right?).  I
   don't have BJ93 w/ me? What reference does it give for trd.dat?  Scott should fix this in
   the revised MBH98 data list:
   [1]ftp://holocene.evsc.virginia.edu/pub/sdr/temp/nature/MANNETAL98/PROXY/mbh98datasummary.t
   xt
   In any case, this hardly constitutes  "considerably more overlap". This represents 1
   series/indicator out of 415 series/112 indicators used.
   So, in total, there are 24 density series used out of a total of 415 proxy indicators, in
   the MBH98 network. Its fair to say this comprises a "very small fraction" of the network,
   but of course we must be careful to point out that the two networks are therefore not
   entirely independent. I will modify the wording in the paper accordingly.
   One final question, was each of the 24 density series in question actually used in the
   Briffa et al MXD network (Tim/Keith?).
   Thanks all for the feedback,
   mike
   At 01:42 PM 1/19/2004 -0700, Malcolm Hughes wrote:

     Mike - there are the following density data in that set:
     1) 20 Schweingruber/Frttss series from the ITRDB (those that
     met the criteria described in the Mann et al 2000 EI paper)
     2) Northern Fennoscandia reconstruction (from Keith)
     3) Northern Urals reconstruction (from Keith)
     4) 1 density series for China (Hughes data) and one from India
     (also Hughes data) - neither included in Keith's data set, I think.
     5) To my great surprise I find that you used the Briffa gridded
     temperature reconstruction from W. N. America (mis-attributed
     to Fritts and Shao) - of course I should have picked up on this 6
     years ago when reading the proofs of the Nature sup mat. It was
     my understanding that we had decided not to use these
     reconstructions, as the data on which they were based were in the
     ITRDB, and had been subject to that screening process. So
     depending on whether you used the long or the shorter versions
     of these, there will have been a considerable number of density
     series included , some of them twice. It means that there is
     considerably more overlap between the two data sets, in North
     America, than I have been telling people. I stand corrected.
     Cheers, Malcolm
     .
     .Malcolm Hughes
     Professor of Dendrochronology
     Laboratory of Tree-Ring Research
     University of Arizona
     Tucson, AZ 85721
     520-621-6470
     fax 520-621-8229

   ______________________________________________________________
                       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
            [2]http://www.evsc.virginia.edu/faculty/people/mann.shtml

