Section 1.9 Response

The terms of reference are as follows:

1.1 Examine the hacked e-mail exchanges, other relevant e-mail exchanges and any other information held at CRU to determine whether there is any evidence of the manipulation or suppression of data which is at odds with acceptable scientific practice and may therefore call into question any of the research outcomes.

ISSUES ARISING ON Para 1.1 OF THE TERMS OF REFERENCE

1. The allegation of ignoring potential problems in deducing palaeotemperatures from tree ring data that might undermine the validity of the so-called “hockey-stick” curve. In the late 20th century, the correlation between the tree ring record and instrumental record of temperature change diverges from that for the earlier period. The cause of this divergence does not appear to be understood. If the method used to deduce temperatures from tree ring proxy metrics for the earlier tree ring record is applied to the late 20th century tree ring series, then declining temperatures would be deduced for the late 20th century. It is alleged that if the cause of divergence between the tree ring and instrumental temperature record is unknown, it may have existed in earlier periods.  Therefore if tree rings had similarly failed to reflect the warming of the early Middle Ages, they may significantly under- estimate the warming during the Medieval Warm Period, thus falsely enhancing the contrast between the recent warming and that earlier period.  (It is this contrast that has led to statements that the late 20th century warming is unprecedented during at least the last 1000 years.)

QUESTIONS TO ADDRESS: 

9. Have you been selective in utilizing tree ring evidence from Yamal in Siberia; and if so, what is the justification for selectivity and does the selection influence the deduced pattern of hemispheric climate change during the last millennium?

Advertisements

23 Responses to “Section 1.9 Response”

  1. Jimchip Says:

    1132094873 Nov 15, 2005 (Briffa to Mann):

    “As others have said , the dating of the chronology in the Urals is not
    wrong – but the magnitude of the extreme years in the early Urals reconstruction were not adjusted to account for inflated variance related to low chronology replication – so they are sort of right that the emphasis on 1032 is probably overdone…”

  2. Jimchip Says:

    1127491287 and http://climateaudit.org/2005/09/26/updated-polar-urals-data/

    From: Keith Briffa
    To: t.m.melvin@uea.ac.uk
    Subject: Polar Urals
    Date: Fri Sep 23 12:01:27 2005

    Tom,
    Can you crossdate these two series (trw and mxd) for the Polar Urals?
    Particularly check the 1032 value when only 3 samples.
    Found this on the blogg site that Tim sent round. Whatever you do,
    don’t respond on the blogg.
    Cheers
    Phil and Keith

  3. jimchip Says:

    1172776463.txt

    http://climateaudit.org/2010/01/04/what-happened-to-polar-urals/

    From: “Tim Osborn”
    To: “Keith Briffa”
    Subject: Re: ppt
    Date: Thu, 1 Mar 2007 14:14:23 -0000 (GMT)
    Reply-to: t.osborn@uea.ac.uk
    Cc: t.osborn@uea.ac.uk

    Here is the old version for you to compare with… the only noticeable
    difference is for the URALS/YAMAL region, which previously had a higher
    peak near 1000 AD. Although that was quite a big change, once you average
    it with the other two series, the overall mean series shows very little
    difference.

    Cheers

    Tim

  4. jimchip Says:

    http://climateaudit.org/2010/01/04/difference-in-yamal-versions-not-insignificant/

    In July 2003, Tim Osborn advised Tom Crowley that there were multiple versions of Yamal (and Tornetrask) and that he needed to contact Briffa prior to using:
    The other files are “tornad.rcs” and “yamal.rcs” which are RCS-standardised tree-ring width series. I would really strongly suggest that you contact Keith Briffa about exactly what these series are..

  5. jimchip Says:

    1146252894.txt

    From: Keith Briffa
    To: t.m.melvin@uea.ac.uk
    Subject: Fwd: Re: Standardisation uncertainty for tree-ring series
    Date: Fri Apr 28 15:34:54 2006

    “URALS” (which includes the Yamal and Polar Urals long chronologies, plus other shorter
    ones). These fall mainly within these 3 boxes:
    52.5E, 67.5N
    62.5E, 62.5N (note this is the only one not at 67.5N)
    67.5E, 67.5N
    “TAIMYR” (which includes the Taimyr long chronology, plus other shorter ones). These
    fall mainly within these 4 boxes:
    87.5E, 67.5N
    102.5E, 67.5N
    112.5E, 67.5N
    122.5E, 67.5N
    We do some analysis at the group scale, and for this we take the JJA temperatures from
    each box and average to the group scale to obtain a single series from each of SCAND,
    URALS and TAIMY.
    We do some analysis at the overall scale, and for this we take these three group
    temperature series and average them to get an overall NW Eurasia temperature for boxes
    with tree chronologies in them.
    We did also try using a wider average for the region, including all LAND temperatures
    from grid boxes within a rectangular region from 12.5E to 127.5E and from 57.5N to
    72.5N, but I don’t think it correlated so well against the tree-ring width data (I can’t
    remember the exact correlations), so we didn’t pursue that.

  6. jimchip Says:

    1090436791.txt

    From: Phil Jones

    To: t.m.melvin@uea.ac.uk
    Subject: Polar Urals
    Date: Wed Jul 21 15:06:31 2004

    Tom,
    Can you send me via email the two sets of results you showed this morning of
    the dating for the trw and mxd series from the Polar Urals? Just the two separate
    ones – forget Yamal.
    Cheers
    Phil

  7. jimchip Says:

    http://climateaudit.org/2006/02/21/more-on-the-yamal-substitution/

    http://climateaudit.org/2006/02/21/yamal-substitution-3/

    http://climateaudit.org/2006/02/22/wilson-on-yamal-substitution/

  8. Jimchip Says:

    Gavin’s Guru and RCS Standardization

    http://climateaudit.org/2009/10/04/gavins-guru-and-rcs-standardization/

  9. Jimchip Says:

    http://climateaudit.org/2009/09/03/kaufmann-and-upside-down-mann/

    The problem with these sorts of studies is that no class of proxy (tree ring, ice core isotopes) is unambiguously correlated to temperature and, over and over again, authors pick proxies that confirm their bias and discard proxies that do not. This problem is exacerbated by author pre-knowledge of what individual proxies look like, leading to biased selection of certain proxies over and over again into these sorts of studies.

    We’ve seen this sort of problem with the Yamal tree ring series (22), which has been discussed at CA on many occasions. (See for example the discussion in the latter part of http://climateaudit.files.wordpress.com/2008/09/mcintyre.2008.erice.pdf ). Briffa originally used the Polar Urals site to represent this region and this data set was used in MBH98-99 and Jones et al 1998. This data set was updated in the late 1990s, resulting in an elevated Medieval Warm Period. Briffa did not report on the updated data; it has never been reported. The data only became available after quasi-litigation with Science in connection with data used in Esper et al 2002. Instead of using the updated Polar Urals version with an elevated MWP, Briffa constructed his own chronology for Yamal, yielding a hockey-stick shaped result. The Yamal substitution has been used in virtually every subsequent study (a point noted by Wegman et al 2006) and is used once again in Kaufman et al 2009. In other studies, a simple replacement of the Yamal version with the updated Polar Urals version impacts the medieval-modern relationship and this needs to be considered here.

    On the other hand, a long Siberian tree ring series known to have an elevated MWP is not used: the Indigirka River (Siberia) tree ring series was used in Moberg et al 2005, but is not used in this study, though it is a long chronology in the same sort of region.

    They use Briffa’s version of Tornetrask (as a leading component of their Fennoscandia (#18). Tornetrask is used in virtually every reconstruction, a point made on many occasions at CA (also see Wegman et al 2006). An updated Tornetrask version (Grudd 2008) had an elevated medieval warm period – see discussion in http://climateaudit.files.wordpress.com/2008/09/mcintyre.2008.erice.pdf).

  10. Jimchip Says:

    Briffa’s response to Yamal (Briffa 2000)
    http://www.cru.uea.ac.uk/cru/people/briffa/yamal2000/

    http://climateaudit.org/2009/09/26/briffas-yamal-crack-cocaine-for-paleoclimatologists/

    http://climateaudit.org/2009/10/01/keith-briffa-responds/

  11. Jimchip Says:

    Miracles and Strip Bark Standardization
    http://climateaudit.org/2009/11/16/luckman-at-the-canadian-society-for-petroleum-geologists/

    Steve: John A, the trouble with going a bridge too far is that people use such overstatements to discredit the valid points. It’s not true that “no one” can be bothered taking multiple cores – at least 2 cores is supposed to be standard practice and Schweingruber, for example, was pretty consistent about taking 2 cores. Unfortunately the most popular multiproxy chronologies tend to be from one-core chronologies: Yamal, Taimyr, Graybill. Odd, isn’t it.

  12. Jimchip Says:

    Is Yamal Homogeneous? An Esper-Style Answer.
    http://climateaudit.org/2009/11/11/is-yamal-homogeneous-an-esper-style-answer/

  13. Jimchip Says:

    Yamal: A “Divergence” Problem

    http://climateaudit.org/2009/09/27/yamal-a-divergence-problem/

    The second image below is, in my opinion, one of the most disquieting images ever presented at Climate Audit.

    Two posts ago, I observed that the number of cores used in the most recent portion of the Yamal archive at CRU was implausibly low. There were only 10 cores in 1990 versus 65 cores in 1990 in the Polar Urals archive and 110 cores in the Avam-Taimyr archive. These cores were picked from a larger population – measurements from the larger population remain unavailable.

    One post ago, I observed that Briffa had supplemented the Taimyr data set (which had a pronounced 20th century divergence problem) not just with the Sidorova et al 2007 data from Avam referenced in Briffa et al 2008, but with a Schweingruber data set from Balschaya Kamenka (russ124w), also located over 400 km from Taimyr.

    Given this precedent, I examined the ITRDB data set for potential measurement data from Yamal that could be used to supplement the obviously deficient recent portion of the CRU archive (along the lines of Brifffa’s supplementing the Taimyr data set.) Hantemirov and Shiyatov 2002 describe the Yamal location as follows:

  14. Jimchip Says:

    Briffa’s Avam-Taimyr Series
    http://climateaudit.org/2009/09/26/briffas-avam-taymir-series/

    Before continuing with Yamal, I’m going to make a little detour through the Avam-Taimyr series, the measurement data to which was also archived at the same time as the Yamal data. Taimyr, also originating in Briffa 2000, has been another staple of Team reconstructions in the past 10 years, but doesn’t have a HS pattern. Actually it had a noticeable Divergence Problem, with a 20th century peak in 1942.

    While Yamal stayed unchanged in Briffa et al 2008, the Taimyr series was modified noticeably, becoming the “Avam-Taimyr” series. To the previous Taimyr site (72N, 101E), Briffa added the Bol’shoi Avam site (70 30N 93E), about 8 degrees (!) to the west. One doesn’t expect Team adjustments to leave even small scraps on the table and this proved to be the case here as well – the added data substantially increased 20th century values and substantially lowered 1150-1250AD values, thereby altering the medieval-modern differential in favor of the 20th century.

  15. Jimchip Says:

    http://climateaudit.org/2009/09/27/yamal-a-divergence-problem/

    The Yamal chronology has always been an exception to the large-scale “Divergence Problem” that characterizes northern forests. However, using the Schweingruber population instead of the 12 picked cores, this chronology also has a “divergence problem” – not just between ring widths and temperature, but between the two versions.

    Perhaps there’s some reason why Schweingruber’s Khadyta River, Yamal larch sample should not be included with the Yamal subfossil data. But given the use of a similar Schweingruber data set in combination with the Taimyr data (in a case where it’s much further away), it’s very hard to think up a valid reason for excluding Khadyta River, while including the Taimyr supplement.

  16. Jimchip Says:

    WSJ on McIntyre, mentions Briffa 2000
    http://online.wsj.com/article/SB10001424052748704335904574496850939846712.html

  17. Jimchip Says:

    1064946297.txt Not Siberia but typical of their selection techniques. Links placed in 1.7 and 3.2 referring to here.

    From: Irina Fast
    To: Tim Osborn , Keith Briffa
    Subject: COLD season T reconstruction
    Date: Tue, 30 Sep 2003 14:24:57 +0200
    Reply-to: f14@zedat.fu-berlin.de

    Hi Tim, hi Keith,

    attached you can find my reconstruction of the cold season temperature
    anomalies. I have retained the 3rd, 4th, 5th and 6th EOFs for the whole time
    span (1500-1976). It seems to be a rather strange choice, but if I retain the
    1st and/or 2nd EOFs the reconstructed T anomalies for Northern Europe are too
    large in comparison to observed anomalies.
    You will see that calibration/verification skills are miserable. But it puts
    my mind to rest, if you say, that this is an expected result.

    Last week you wrote :
    >Please let us (me and Keith) know if you are happy with your implementation
    >of the Mann et al. method. I remember that you had some strange results
    >when you applied it to the model simulations – did you solve those
    >problems? We might be able to help or provide advice if you still have
    >problems with the method.
    The problems I mentioned at the meeting in France arose if I applied my
    implementation of the method to the INSTRUMENTAL data and I tried to explain
    this effect through the gaps in the data. In the meantime I was able to
    eliminate to some degree this problem through the use of other fortran
    compiler and numeric library. I will prepare an slide with assesment of the
    performance of the current method implementation for “perfect proxy data”
    (i.e. instrumental data as proxy data).

    And now some words to agenda
    1) Antje Weisheimer will say initial greeting words and make all
    organisational announcments.
    2) As you know, Ulrich take part in the analysis of the simulations performed
    with ECHO-G by GKSS group. I am not sure, but maybe he will also present his
    ideas for further (in framework of SO&P reasonable) simulations, that can be
    conducted by FUB.

    For the presentations both OHP and data projector are available.

    Best redards
    Irina

    ________________________________________________________
    Irina Fast
    Freie Universität Berlin

  18. Jimchip Says:

    Treering wiki including discussion of the corridor method disparaged for some data sets. Link posted also in Sec. 4.6
    http://www.cybis.se/wiki/index.php?title=Corridor_method

  19. Jimchip Says:

    McIntyre to Jeff Id discussion referenced on listserve
    http://listserv.arizona.edu/cgi-bin/wa?A2=ind0910&L=itrdbfor&T=0&P=1375

    Steve McIntyre responds to a similar question at Climate Audit::

    “Re: Jeff Id (#157),

    Jeff, to my recollection, I haven’t specifically discussed corridor
    standardization here before. It’s a Russian method which was discussed
    in some dendro workshops in the 1990s. Some comparisons were made to
    “conventional” (tree-by-tree) standardization (not one-size-fits-all
    RCS standardization) and they were found to be pretty similar.
    “conventional” standardization as applied to “short”-lived trees (
    e.g. under 250 years) will not recover centennial variability; the
    graphs have a distinctive look that is shared by the H and S
    chronology at NCDC.

    “There’s a useful article in the NATO 1996 conference (ed Jones,
    Bradley, Jouzel) that I’ll try to scan some time.”

    Maybe that will suggest where to look.
    Juan

  20. Jimchip Says:

    http://listserv.arizona.edu/cgi-bin/wa?A2=ind0910&L=itrdbfor&T=0&P=2389

    Date: Wed, 7 Oct 2009 07:23:54 -0700
    Reply-To: ITRDB Dendrochronology Forum
    Sender: ITRDB Dendrochronology Forum
    From: Jim Bouldin
    Subject: Re: “corridor” standardization; Prometheous
    Comments: To: “juanslayton @[log in to unmask]”

    It was McIntyre who originally raised the issue with his multiple recent posts criticizing a 2000 work of Keith Briffa, which uses the data of the Russians previously referred to, but with the RCS standardization method instead of the corridor standardization used by the Russians, as mentioned in their 2002 paper (and previously): Hantemirov and Shiyatov, 2002, A continuous multimillennial ring-width chronology in Yamal, northwestern Siberia. The Holocene 12: 717–726. I have responded at length to some of McIntyre’s assertions at RealClimate and Climate Audit over the last couple days. I also found another description of the procedure, and comparison to ARSTAN-based methods, by Shiyatov and others, beginning on pdf page 22 of this document: http://www.fs.fed.us/ne/newtown_square/publications/other_publishers/OCR/ne_1989_noble001a.pdf Jim Bouldin UC Davis

  21. Jimchip Says:

    1074609944.txt Long Briffa email discussing various series.

    From: Keith Briffa
    To: “Malcolm Hughes” , “Malcolm Hughes” , Tim Osborn ,”Michael E. Mann”
    Subject: Re: J. Climate paper – in confidence
    Date: Tue, 20 Jan 2004 09:45:44 +0000
    Cc: Scott Rutherford

    Malcolm seems to have done a good job sorting out these constituent sets ,
    and I don’t have anything to add other than agreeing that as a general
    principal , where possible, original chronologies should be used in
    preference to reconstructed temperature series ( the latter having been
    already optimized using simple or multiple regression to fit the target
    temperature series ). This applies not only to our western US
    reconstructions (which it should be stressed are based on very flexible
    curve fitting in the standardisation – and inevitably can show little
    variance on time scales longer than a decade or so) but also to the
    Tornetrask and Polar Urals reconstructions (each of which was based on ring
    width and density data , but standardised to try to preserve centennial
    variability – though the density series had by far the largest regression
    coefficients). There is though a question regarding the PCs of the Siberian
    network (presumably provided by Eugene?) . The correlation between density
    and ring width can get high in central and eastern parts of the network ,
    so even though these are different variables , it might not be strictly
    true to think of them as truly independent (statistically) of the density
    chronologies we use from the Schweingruber network ( there may also be a
    standardisation issue here , as the density chronologies were standardised
    with Hugershoff functions for our initial network work (as reported in the
    Holocene Special Issue) whereas your PC amplitudes may be based on
    “Corridor Standardisation” – which likely preserves less low frequency? ) .
    These remarks are simply for clarification and discussion , and I too will
    wait on your response draft , though I would throw in the pot the fact that
    omitting the time dependent stuff would simplify the message at his stage.
    cheers
    Keith

    At 01:42 PM 1/19/04 -0700, Malcolm Hughes wrote:
    >Mike – there are the following density data in that set:
    >1) 20 Schweingruber/Frttss series from the ITRDB (those that
    >met the criteria described in the Mann et al 2000 EI paper)
    >2) Northern Fennoscandia reconstruction (from Keith)
    >3) Northern Urals reconstruction (from Keith)
    >4) 1 density series for China (Hughes data) and one from India
    >(also Hughes data) – neither included in Keith’s data set, I think.
    >5) To my great surprise I find that you used the Briffa gridded
    >temperature reconstruction from W. N. America (mis-attributed
    >to Fritts and Shao) – of course I should have picked up on this 6
    >years ago when reading the proofs of the Nature sup mat. It was
    >my understanding that we had decided not to use these
    >reconstructions, as the data on which they were based were in the
    >ITRDB, and had been subject to that screening process. So
    >depending on whether you used the long or the shorter versions
    >of these, there will have been a considerable number of density
    >series included , some of them twice. It means that there is
    >considerably more overlap between the two data sets, in North
    >America, than I have been telling people. I stand corrected.
    >Cheers, Malcolm

  22. Jimchip Says:

    1074612429.txt Mann involved with the previous series discussion.

    From: “Malcolm Hughes”
    To: Keith Briffa , “Malcolm Hughes” , Tim Osborn , “Michael E. Mann”
    Subject: Re: J. Climate paper – in confidence
    Date: Tue, 20 Jan 2004 10:27:09 -0700
    Cc: Scott Rutherford , mann@virginia.edu

    Mike – you are right that we should probably leave the network
    uncahnged for this mss. In fact, however, as Keith indicated, the
    Vaganov data probably retained a fair amount of low frequency
    because of the use of the corridor method (i.e. were not “heavily
    standardized”). CHeers, Malcolm
    On 20 Jan 2004 at 7:58, Michael E. Mann wrote:

    > Thanks Keith,
    >
    > I agree w/ this–I think the Vaganov chronologies were pretty heavily
    > standardized, and the other issues you raise are important. In the
    > future, we would (and will) be a bit more circumspect about the use of
    > some of these data.
    >
    > In the present case, however, I think we are forced to use the exact
    > same network.
    >
    > Re, the omission of some results. I think we can probably keep them.
    > Simply by cleaning up the text, removing redundancy, etc. I’ve
    > shortened and tightened the manuscript considerably, and I think I’ve
    > improved the logical flow a bit in the process. So my feeling is that
    > we will not have to split this up, but I’ll leave this to all of you
    > to decide after you see the revised draft from Scott and me…
    >
    > Thanks,
    >
    > mike
    >
    > At 09:45 AM 1/20/2004 +0000, Keith Briffa wrote:
    > Malcolm seems to have done a good job sorting out these
    > constituent sets , and I don’t have anything to add other than
    > agreeing that as a general principal , where possible, original
    > chronologies should be used in preference to reconstructed
    > temperature series ( the latter having been already optimized
    > using simple or multiple regression to fit the target temperature
    > series ). This applies not only to our western US reconstructions
    > (which it should be stressed are based on very flexible curve
    > fitting in the standardisation – and inevitably can show little
    > variance on time scales longer than a decade or so) but also to
    > the Tornetrask and Polar Urals reconstructions (each of which was
    > based on ring width and density data , but standardised to try to
    > preserve centennial variability – though the density series had by
    > far the largest regression coefficients). There is though a
    > question regarding the PCs of the Siberian network (presumably
    > provided by Eugene?) . The correlation between density and ring
    > width can get high in central and eastern parts of the network ,
    > so even though these are different variables , it might not be
    > strictly true to think of them as truly independent
    > (statistically) of the density chronologies we use from the
    > Schweingruber network ( there may also be a standardisation issue
    > here , as the density chronologies were standardised with
    > Hugershoff functions for our initial network work (as reported in
    > the Holocene Special Issue) whereas your PC amplitudes may be
    > based on “Corridor Standardisation” – which likely preserves less
    > low frequency? ) . These remarks are simply for clarification and
    > discussion , and I too will wait on your response draft , though I
    > would throw in the pot the fact that omitting the time dependent
    > stuff would simplify the message at his stage. cheers Keith
    >
    > At 01:42 PM 1/19/04 -0700, Malcolm Hughes wrote:
    > Mike – there are the following density data in that set:
    > 1) 20 Schweingruber/Frttss series from the ITRDB (those that
    > met the criteria described in the Mann et al 2000 EI paper)
    > 2) Northern Fennoscandia reconstruction (from Keith)
    > 3) Northern Urals reconstruction (from Keith)
    > 4) 1 density series for China (Hughes data) and one from India
    > (also Hughes data) – neither included in Keith’s data set, I
    > think. 5) To my great surprise I find that you used the Briffa
    > gridded temperature reconstruction from W. N. America
    > (mis-attributed to Fritts and Shao) – of course I should have
    > picked up on this 6 years ago when reading the proofs of the
    > Nature sup mat. It was my understanding that we had decided not to
    > use these reconstructions, as the data on which they were based
    > were in the ITRDB, and had been subject to that screening process.
    > So depending on whether you used the long or the shorter versions
    > of these, there will have been a considerable number of density
    > series included , some of them twice. It means that there is
    > considerably more overlap between the two data sets, in North
    > America, than I have been telling people. I stand corrected.
    > Cheers, Malcolm

  23. sonicrafter Says:

    I feel more men and women will need to read this, extremely beneficial info.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: