Friday, December 16, 2011


From: Jonathan Overpeck <>
To: Keith Briffa <>
Subject: Re: Fwd: Re: updated MWP figure
Date: Tue, 28 Jun 2005 10:11:05 -0600
Cc: Eystein Jansen <>

Hi Keith - might be worth talking on the phone - you, me and Eystein
- after you get back. You could be right, but it is a powerful way to
look at the issue. The question is whether the normalization could be
preventing a warmer than late-20th century signal from appearing?

Should we instead update the Bradley Science graphic? That's not as
effective in my opinion.

So, let's talk next week?

Going to a tree day meeting or a three day meeting - it has to be
tough looking at tree data all day.

have fun, thx, peck

>Jonathan and Eystein
>I am leaving very early for a tree day meeting in Swansea , and will
>be away til Monday. Presently buried in EC Reporting and other stuff
>- but the reason I dislike the MWP Figure is that the simple
>normalization of series as done , (regardless of regional selection
>of specific proxies) gives a largely random amplitude to the various
>records , depending on their spectral character, and of course,
>equal weight to all regardless of the strength of their link with
>local or NH temperatures). I will think about this - you are the
>ultimate arbiter anyway .
>sorry to be so abruptly communicative
>At 16:10 28/06/2005, you wrote:
>>Hi Tom -- thanks for the extra effort. I'm pushing others on the
>>author team to think hard about such a figure (space may end up
>>being the hardest part), and I should have something to discuss w/
>>you soon. Thanks for being willing to shift priorities if needed.
>>FYI - I just got reviews back from an EOS piece that took over a
>>1.5 months to get. And of course, they want some edits. Not the
>>speedy venue we once knew a loved, although I bet if you really
>>keep it short and sweet it might go faster.
>>Best, more soon, peck
>>>X-Sieve: CMU Sieve 2.2
>>>Date: Tue, 28 Jun 2005 10:13:49 -0400
>>>From: Tom Crowley <>
>>>X-Accept-Language: en-us, en
>>>To: Jonathan Overpeck <>
>>>Cc: Eystein Jansen <>
>>>Subject: Re: updated MWP figure
>>>Hi Jonathan,
>>>let me answer the last question first - there are actually not
>>>many records that go back that far and I have used, I think, every
>>>one except Quelcaya, which being from the southern tropics makes
>>>for a lonely but potential future inclusion (which makes no
>>>difference on the conclusion).
>>>several of the sites include multiple time series - e.g., western
>>>U.S. time series, w. Siberia time series, e. Asia, and w.
>>>Greenland. I did not want to overweight any site though because
>>>of the need for a geographic balance -- note that there are four
>>>sites each in the w. hemisphere and e. hemisphere, and that the
>>>distribution of sites in each hemisphere represents a good scatter.
>>>for almost all of these sites the references are easily imaginable
>>>based on the location of the site, but they can be provided if you
>>>are interested in including the figure.
>>>can you think of any long sites I have not included? right now I
>>>in the overlap interval of 1500-1850 our composite has highly
>>>significant correlations with the Mann, Jones, and Briffa
>>>reconstructions that contain much more data -- thereby suggesting
>>>that use of only long time series provides a "reasonable" estimate
>>>of the last 1100 years.
>>>I have not submitted this for publication but if you are
>>>interested in including this in ipcc I can knock off a tutorial
>>>note to eos on short notice.....
>>>I am attaching the figure in several different alternate formats -
>>>cannot easily do the two you suggest from my mac, but again I can
>>>get that done with more work if you are interested - let me know
>>>where to go next - note that I originally sent this along fyi,
>>>only to be used if you thought the figure was worthwhile -- if not
>>>I will just reorder the priority of writing it up as a note,
>>>Jonathan Overpeck wrote:
>>>>Hi Tom - thanks for sending this plot. I'm a bit late in
>>>>responding since we were moving to (and still into) our
>>>>sabbatical digs in SW CO.
>>>>Would you be willing to provide more on this plot in order for me
>>>>to understand it better? I personally like the plot quite a bit,
>>>>but between the space restrictions and other's assessment,
>>>>whether we use it or not will take some real thinking.
>>>>For example, it would help to have
>>>>1) a higher resolution version - eps or ai?
>>>>2) a caption or text that would spell out which records are
>>>>included, and their origins (references)
>>>>3) a bibliography for those refs.
>>>>4) perhaps, you have a paper with this included? If so, can you
>>>>send a prerprint?
>>>>5) some discussion of why you used the series (sites) you did,
>>>>and not others - more specifically, what's wrong with others?
>>>>If you don't mind helping here, I'll promise to get it in the mix
>>>>for serious discussion. Of course, it's already in the mix since
>>>>Eystein forwarded to Keith, and you Tim, but I want to weigh in
>>>>as informed as possible. Trying to keep track of a lot, so your
>>>>help is much appreciated.
>>>>Thanks! Peck
>>>>>I have been fiddling with the best way to illustrate the stable
>>>>>nature of the medieval warm period - the attached plot has eight
>>>>>sites that go from 946-1960 in decadal std. dev. units -
>>>>>although small in number there is a good geographic spread --
>>>>>four are from the w. hemisphere, four from the east. I also
>>>>>plot the raw composite of the eight sites and scale it to the
>>>>>30-90N decadal temp. record.
>>>>>this record illustrates how the individual sites are related to
>>>>>the composite and also why the composite has no dramatically
>>>>>warm MWP -- there is no dramatically warm clustering of the
>>>>>individual sites.
>>>>>use or lose as you wish, tom
>>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

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

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