cc: Tim Osborn <t.osborn@uea.ac.uk>, Keith Briffa <k.briffa@uea.ac.uk>
date: Sun, 22 Jun 2003 21:01:40 -0400
from: "Michael E. Mann" <mann@virginia.edu>
subject: Re: Yang et al
to: "Raymond S. Bradley" <rbradley@geo.umass.edu>, p.jones@uea.ac.uk, mhughes@ltrr.arizona.edu, wigley@ncar.ucar.edu

   Hi Ray,
   I'm in Volcano national park on my Honeymoon, so comment will be brief, by necessity...
   In our GRL article, Phil and I weighted the records we used with respect to their decadal
   correlations with the instrumental gridpoint surface temperature data for the same region
   (numbers in parentheses in attached figure 1 from the paper), so if a series is truly crap
   in an objectively determined sense, it got very low weight. The China series has a
   reasonable (r=0.22), but not great correlation--and it  gets a moderate low weight.
   In my opinion, this is a better approach then simply deeming a record crap a priori (and
   then getting criticized for not considering it). We considered all available records with
   appropriate resolution that are putative temperature estimates, and weighted them
   objectively.
   We also did careful cross-validation on the resulting reconstruction using independent
   instrumental data, etc.---so I hardly think we are subject to criticism in how we used the
   available data, relative to other analyses that have been done...
   As for the Eos piece, I think a similar point holds--not showing it at all would seem a
   conspicuous omission. We could add the local correlation values to each of the panels of
   Figure 2, and comment briefly--this could be done at the proof stage.
   I'll leave this to Phil (or Keith or Tim, who are helping out since Phil is also on
   vacation) to take care of, as I have promised not to get involved with this sort of stuff
   until my honeymoon is over. Phil and I can discuss this, if need be, when we meet in
   Sapporo in a couple weeks,
   mike
   At 06:37 PM 6/22/2003 -0400, Raymond S. Bradley wrote:

     Phil:
     You commented that the Chinese series of Yang et al (GRL 2002) looked weird.  Well,
     that's because it's crap--no further comment on what stuff gets into GRL!
     You appear to have used their so-called "complete" China record.  You really should
     consider what went into this --2 ice core delta 18O records of dubious relationship to
     temperature (one is cited as correlating with NW China temperatures at r=0.2-0.4), 3
     tree ring series, one of which is a delta C-13 record of questionable climatic
     significance (to be generous).  The other series include two records from a Taiwan
     lake--a carbon/nitrogen isotope and a total organic carbon series (interpreted as
     high="warm, wet") and an oxygen isotope series from cellulose in peat!!! (& don't ask
     about the C-14 based chronology, interpolated to decadal averages!)
     I loved this sentence:
     "Although a quantitative relationship between the proxy records of the Jinchuan peat,
     the Japan tree-ring series and the Taiwanese sediment records with modern climate data
     are not given in the original works, the qualitative connectivity with temperature as
     the dominant controlling factor has undoubtedly been verified"
     Oh, undoubtedly!!  And these are 4 of the 9 series going into the "complete China"
     record..
     Finally, they use another record based on "phenology" and (somehow) this provides a
     winter temperature series....
     You just shouldn't grab anything that's in print and just use it 'cos it's there---that
     just perpetuates rubbish.  This series needs to be removed from Figure 2 in the EOS
     forum piece--and if you included it in your GRL paper, I suggest that you reconsider it.
     Ray
     Raymond S. Bradley
     Distinguished Professor
     Director, Climate System Research Center*
     Department of Geosciences
     Morrill Science Center
     611 North Pleasant Street
     AMHERST, MA 01003-9297
     Tel: 413-545-2120
     Fax: 413-545-1200
     *Climate System Research Center: 413-545-0659
             <[1]http://www.paleoclimate.org>
     Paleoclimatology Book Web Site: [2]http://www.geo.umass.edu/climate/paleo/html

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