From: Jonathan Overpeck <jto@email.arizona.edu>
To: Darrell Kaufman <Darrell.Kaufman@nau.edu>, Nick McKay <nmckay@email.arizona.edu>, Caspar Ammann <ammann@ucar.edu>, David Schneider <dschneid@ucar.edu>, "Bette L. Otto-Bliesner" <ottobli@ucar.edu>, Raymond Bradley <rbradley@geo.umass.edu>, Miller Giff <gmiller@colorado.edu>, Bo Vinther <bo@gfy.ku.dk>, Keith Briffa <k.briffa@uea.ac.uk>
Subject: Re: Arctic2k update?
Date: Sat, 05 Sep 2009 11:25:02 -0700
Cc: <mann@psu.edu>

   D et al - Please write all emails as though they will be made public.
   I would not rush and I would not respond to any of them until the best strategy is
   developed - don't want to waste anyone's time, including yours or Mc's. Since the recon in
   Science has an error, I think you do need to publish a correction in Science. In that, you
   can very briefly not it didn't affect the calibration, nor the final result. I don't think
   you have a choice here. And I don't think RealClimate alone is the place for this, although
   RC could be good for the bigger list of issues. Don't do it on Mc;s blog. But, it would be
   good to hear from Ray and Mike, since they have the most experience in getting it right.
   Here are some other QUICK thoughts - don't count on me for the next week. Proposal hell and
   traveling.
   Make sure you have Keith's feedback before saying anything about the dendro aspects.
   Don't know about Dye3 issue
   Error analysis should be done and be the topic of another paper - it wasn't included in
   this paper, so it's something that should be done outside the peer-review process. There is
   lots of new research to be done, and someone should do it as time allows. Don't get pushed
   into something too rushed or preliminary, and your defense is that you wrote a paper that
   reviewed well and was published. The goal wasn't to do everything in this paper.
   #4 - your are absolutely right and that could be in a blog someplace, or just let them go
   ahead and do a stupid thing. If this was a climate field recon it would be different, no?
   #5 is tricky. Giving him the data would be good, but only if it is yours to give. You can't
   give him data that you got from others and are not allowed to share. But, it would be nice
   if he could have access to all the data that we used - that's the way science is supposed
   to work. See what Mike and Ray say...
   Be careful, very careful. But now you know why I advocated redoing all the analyses a few
   months ago - to make sure we got it all right. We knew we'd get this scrutiny.
   This paper has had great impact so far, so that's something to remember - its good work.
   Thanks, peck
   On 9/5/09 8:44 AM, "Darrell Kaufman" <[1]Darrell.Kaufman@nau.edu> wrote:

     All:
     I received my first hate mail this AM, which helped me to realize that I shouldn't be
     wasting time reading the blogs.
     Regarding the "upside down man", as Nick's plot shows, when flipped, the Korttajarvi
     series has little impact on the overall reconstructions. Also, the series was not
     included in the calibration. Nonetheless, it's unfortunate that I flipped the
     Korttajarvi data. We used the density data as the temperature proxy, as recommended to
     me by Antii Ojala (co-author of the original work). It's weakly inversely related to
     organic matter content. I should have used the inverse of density as the temperature
     proxy. I probably got confused by the fact that the 20th century shows very high density
     values and I inadvertently equated that directly with temperature.
     This is new territory for me, but not acknowledging an error might come back to bite us.
     I suggest that we nip it in the bud and write a brief  update showing the corrected
     composite (Nick's graph) and post it to RealClimate. Do you all agree?
     There's other criticisms that have come up by McIntyre's group:
     (1) We cherry-picked the tree-ring series in Eurasia. Apparently this is old ground, but
     do we need to address why we chose the Yamal record over the Polar Urals? Apparently,
     there's also a record from the Indigirka River region, which might not have been
     published and doesn't seem to be included in Keith's recent summary. If we overlooked
     any record that met our criteria, I suggest that we explain why. Keith: are you back?
     Can Ray or Mike provide some advise?
     (2) The correction for Dye-3 was criticized because the approach/rationale had not been
     reviewed independently on its own. Bo: has this procedure now been published anywhere?
     (3) We didn't publish any error analysis (e.g., leave-one-out ), but I recall that we
     did do some of that prior to publication. Would it be worthwhile including this in our
     update? The threshold-exceedence difference (O&B-style) does include a boot-strapped
     estimate of errors. That might suffice, but is not the record we use for the temperature
     calibration.
     (4) We selected records that showed 20th century warming. The only records that I know
     of that go back 1000 years that we left out were from the Gulf of Alaska that are known
     to be related strongly to precipitation, not temperature, and we stated this upfront. Do
     we want to clarify that it would be inappropriate to use a record of precip to
     reconstruct temperature? Or do we want to assume that precip should increase with
     temperature and add those records in and show that the primary signals remain?
     (5) McIntyre wrote to me to request the annual data series that we used to calculate the
     10-year mean values (10-year means were up on the NOAA site the same AM as the paper was
     published). The only "non-published" data are the annual series from the ice cores
     (Agassiz, Dye-3, NGRIP, and Renland). We stated this in the footnote, but it does
     stretch our assertion that all of the data are available publicly. Bo: How do you want
     to proceed? Should I forward the annual data to McIntyre?
     Please let me -- better yet, the entire group -- know whether you think we should post a
     revision on RealScience, and whether we should include a reply to other criticism (1
     through 5 above). I'm also thinking that I should write to Ojala and Tiljander directly
     to apologize for inadvertently reversing their data.
     Other thoughts or advise?
     Darrell
     On Sep 4, 2009, at 5:24 PM, Nick McKay wrote:

     The Korttajarvi record was oriented in the reconstruction in the way that McIntyre said.
     I took a look at the original reference - the temperature proxy we looked at is x-ray
     density, which the author interprets to be inversely related to temperature. We had
     higher values as warmer in the reconstruction, so it looks to me like we got it wrong,
     unless we decided to reinterpret the record which I don't remember. Darrell, does this
     sound right to you?

     This dataset is truncated at 1800, so it doesn't enter the calibration, nor does it
     affect the recent warming trend.
     The attached plot (same as before) shows the effect of re-orienting the record on the
     reconstruction. It doesn't change any of our major or minor interpretations of course.

     Nick
     On Thu, Sep 3, 2009 at 4:45 PM, Nick McKay <[2]nmckay@email.arizona.edu> wrote:

     Hi all,
     I haven't checked the original reference for it's interpretation, but I checked the code
     and we did use it in the orientation that he stated. He's also right that flipping
     doesn't affect any of the conclusions. Actually, flipping it makes it fit in better with
     the 1900-year trend.

     I've attached a plot of the original, and another with Korttajarvi flipped.
     Nick

     [cid:3334994702_4110695]

   Jonathan T. Overpeck
   Co-Director, Institute of the Environment
   Professor, Department of Geosciences
   Professor, Department of Atmospheric Sciences
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   Embedded Content: image7.jpg: 00000001,780e1428,00000000,00000000

References

   1. file://localhost/tmp/Darrell.Kaufman@nau.edu
   2. file://localhost/tmp/nmckay@email.arizona.edu
   3. file://localhost/tmp/jto@u.arizona.edu
   4. file://localhost/tmp/regalado@email.arizona.edu

