Thursday, April 12, 2012


cc: Keith Briffa <>, Jonathan Overpeck <>, Eystein Jansen <>
date: Thu, 21 Jul 2005 12:54:14 -0400
from: Tom Crowley <>
subject: Re: MWP figure
to: Tim Osborn <>

Tim, we are getting close but there are a few items to discuss:

1) seven of the eight time series are from the Hegerl et al paper, now
out for review in Nature
2) the eighth time series is from Brian Luckmans recent extension of the
Alberta record to the 10th century - we used his original time series in
the H et al paper because the comparisons between model and observations
had been going on for a while, in fact before the new Luckman paper came
out, and we did not want to switch horses in midstream by changing the
composite - as you know the Luckman paper is either accepted or
published in CD, so there is no problem changing that
3) although technically the time series are not the same they are very
close, if you want me to do some comparisons I can, but I could not get
to it until probably tuesday of next week - I don't particularly see any
problem in makng such an addition
4) we cannot extend the time series back to 800 without dropping out
something - the reason we start at 945 is that is the first year when
all the records are available - if we go back to 800 we do so at the
cost of dropping 2 or possibly even 3 records. as our Dark Ages
reconstruction starting at 560 indicates (att.), the biggest warming
between 800-1900 is in the late 10the century (960-995), we did not
think we missing out on anything by starting at 945 rather than 800.

I await your feedback on this increasingly intricate issue, tom

Tim Osborn wrote:

> Hi Tom,
> In Keith's email below, when he says "we use series that total to
> Tom/Gabi composite", he doesn't mean that *our* mock up of the figure
> uses these series, but that if the series shown in *your* draft figure
> are the same as those used in the Hegerl/Crowley recon that is
> currently submitted ("...a twice validated climate record...") then we
> will go with *your* figure. It is fine then to include the "composite
> series" and the instrumental data and a temperature scale. Our
> previous concerns about these latter points were that it might be seen
> as another new NH temperature reconstruction. But if in fact the
> composite and its expression as a temperature are not a new NH T
> recon, but are in fact identical to the published (submitted, at
> least) Hegerl/Crowley NH T recon (which is already included in the
> main intercomparison figure) then there's no problem.
> Does your figure equate to the new Hegerl/Crowley NH T recon? If so,
> we should go with your MWP figure, though the CLAs want me to draw it
> in the same style as the others and also cut the time period down to a
> few centuries spanning the MWP. Keith suggests beginning in 800 or 850.
> Would it be possible therefore to send the data series you used for
> your figure, but beginning in 800/850, so I can plot the figure in the
> required form?
> Cheers
> Tim
> At 14:53 20/07/2005, Tom Crowley wrote:
>> Keith, if you can find more I see no problem - it seems that a lot of
>> the data you used was via Cook and colleagues - I was unable to
>> locate a full length record from Quebec in that time series, but
>> maybe you are relying on something else - if so can I have it!?
>> other suggestions: provide a more general label to sites - eg,
>> mangazeyek (sp)/yamal could be listed as polar urals - taimyr
>> central Siberia.
>> China shoudl be relabeled as east Asia as it does include some
>> information from Japan and the Tibetan Plateau (L. Thompson) and we
>> don't want to get into some political to-do by calling Tibet "Chinese".
>> that's all I can think of for present, good sailing, tom
>> Keith Briffa wrote:
>>> 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.)
>>> cheers
>>> Keith
>>> .
>>> 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 selected.
>>>> 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 figure.
>>>> 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
> Dr Timothy J Osborn
> Climatic Research Unit
> School of Environmental Sciences, University of East Anglia
> Norwich NR4 7TJ, UK
> e-mail:
> phone: +44 1603 592089
> fax: +44 1603 507784
> web:
> sunclock:


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