Monday, April 9, 2012


cc: Eystein Jansen <>,
date: Wed Jul 20 12:18:22 2005
from: Keith Briffa <>
subject: Re: CLA feedback on Tom and the MWP
to: Jonathan Overpeck <>, Tom Crowley <>

Hi all
think this is resolved now (virtually) -
We use series that total to Tom/Gabi composite , and we can cite this as an example of the
scatter of regional records "in a typical reconstruction". This avoids very difficult issue
of what is the best way to aggregate certain data sets - we are simply illustrating the
point with one published (by then) data set.
The issue of the composite is then not an issue either , because it is not a new
(unpublished) composite that we were concerned about - though I still believe it is a
distraction to put the composite in. It would be best to use data from 800 or 850 at least
, and go to 1500 (?) and presumably normalise over the whole period of data shown. OK? Even
though you guys all wish to go with the reduced period (ie not up the present) , but my own
instinct is that this might later come back to haunt us - but will take your lead.
I agree the look of the Figure should match the others.
So, if Tom will send the data sets (his regional curves) , Tim will plot and send back asap
for scrutiny. Thanks Tom and thanks for your help with this - further comments on latest
version of 6.5 (last 2000 years) still welcome , though will be incorporating a few changes
in response to David and Fortunat input , and SH bit (from Ricardo and Ed) still to go in
and regional section to be revised (after input from Peck et al.)

At 21:42 19/07/2005, Jonathan Overpeck wrote:

Hi Keith and Tim: Just got off the phone with Eystein, and hopefully he will sleep ok
knowing that we have a plan for the MWP fig and Tom...
Please ask questions if we don't cover all the key points, but here's what we think:
1) the MWP fig should span the MWP only, and should emphasize variation in regional
amplitude (we agree that we must be clear that this fig is not a reconstruction) - that
is, it is best to use time series representing regions, assuming that the regional
series do represent a region ok with one or more input series. We want to avoid a
regional bias if we can - this is what got us into all the MWP misunderstanding in the
first place, perhaps (e.g., nice MWP in Europe/Atlantic region - must be global)
2) If you guys could agree on the series and the interval, that'd be great. We agree it
would be good to start before 1000 and end before the Renaissance (15th century?). If
you want more feedback on these issues, we're happy to provide, but it seems logical
that you pick series and intervals so that each series covers the entire interval
3) Don't use the Chesapeak record - it is likely biased by salinity
4) We'd like Keith and Tim to draft the final figure so that it matches the look and
style of the other two figs they have made. Hope this is doable. Tom, does Keith have
all the data? Thanks for sending if not.
5) We agree that Tom should NOT be a CA given that he was officially one of the ZOD
reviewers. Of course, this doesn't represent a real conflict, but we need to avoid even
the appearance of conflict. We greatly appreciate all the feedback that Tom is
providing! Is this plan ok w/ you Tom? We think you're cool with it, but just want to
check one more time.
That... it is. Please let us know if there are any more questions. Keith - feel free to
try and get Eystein on his cell doing your work hours if you want quick feedback. Or we
can do this by email - he's not in a very email friendly place right now, but the
fishing appears to be ok.
Again, thanks to you both for all the discussion and thought that has gone into this
Best, peck
Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences
Mail and Fedex Address:
Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795

Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.

Phone: +44-1603-593909
Fax: +44-1603-507784

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