Section 3.2 Responses

3. It is alleged that proxy temperature deductions and instrumental temperature data have been improperly combined to conceal mismatch between the two data series An attempt to hide the difficulty of combining these two data series and to mislead is alleged to be revealed in the following sentence in a November 1999 email from Professor Phillip Jones which is alleged to imply a conscious attempt to mislead: “I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (i.e. from 1981 onwards) and from 1961 for Keith’s to hide the decline”. 

QUESTIONS TO ADDRESS

 2. How do you justify combining proxy and instrumental data in a single plotted line?

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6 Responses to “Section 3.2 Responses”

  1. Jimchip Says:

    0963233839 0 Jul 2000 “Raymond S. Bradley” to Frank Oldfield (see also 1.2):

    “Sorry this kept you awake…but I have also found it a rather alarming graph. First, a disclaimer/explanation. The graph patches together 3 things: Mann et al NH mean annual temps + 2 sigma standard error for AD1000-1980, + instrumental data for 1981-1998 + IPCC (“do not quote, do not cite” projections for GLOBAL temperature for the next 100 years, relative to 1998. The range of shading represents several models of projected emissions scenarios as input to GCMs, but the GCM mean global temperature output (as I understand it) was then reproduced by Sarah Raper’s energy balance model, and it is those values that are plotted. Keith pointed this out to me; I need to go back & read the IPCC TAR to understand why they did that”

    and OldField quoted by Bradley: “The questions in my mind centre round the following issues. If I’ve got any >one of them wrong, what follows in each section can be disregarded or (more >kindly) set straight for my benefit. 1. How can we justify bridging proxy-based reconstruction via the last bit >of instrumental time series to future model-based scenarios. 2. How can the incompatibilities and logical inconsistencies inherent in >the past-future comparisons be reduced? 3. More specifically, what forms of translation between what we know about the past and the scenarios developed for the future deal adequately with uncertainty and variability on either side of the ‘contemporary hinge’ in a way that improves comparability across the hinge… 2 & 3. This is where life gets complicated. For the past we have biases, error bars that combine sources of uncertainty, and temporal variability. For the future we have no variability, simply a smooth, mean, monotonic trend to a target ‘equilibrium’ date. Bandwidths of uncertainty reflect model construction and behaviour. So we are comparing apples and oranges when we make any statement about the significance of the past record for >the future on the basis of the graph. Are there ways of partially >overcoming this by developing different interactions between past data and future models?”

    1000154718 10 Sep 2001 (Cook to Briffa):

    “So, the version I am working on covers (hopefully) some of your concerns/complaints. I will do my best to be “fair” before I finally submit it. However, this is a Report to Science (~2500 word limit), so I can’t do the kind of review of the literature and detailed discussiion of results that would be possible in more normal size papers.

    Sorry for sounding a bit testy here. I’ve been fielding a whole raft of questions, comments, and criticisms from Mike Mann, Tom Crowley, and Malcolm Hughes. Some of them useful, many of them tiresome or besides the point. I never wanted to get involved in this quixotic game of producing the next great NH temperature reconstruction because of the professional politics and sensitivities involved. All I wanted to do was demonstate with Jan that Broecker was wrong, something that you have obviously done a few times before but in journals that Broecker and others don’t follow closely (I guess. I should also say that the amount of ignorance about tree rings in the global change/paleo/modeling community is staggering given what has been published. Like it or not, they simply don’t read our papers.). In so doing, it seemed reasonable to compare the RCS chronology against the hockey stick because that is the series that Broecker was railing against.”

    1018539404 4/11/02 Edward Cook to Mann and Hughes, quoted by Mann:

    “I must say at the beginning that some parts of your letter to Science are as “flawed” as your claims about Esper et al. (hereafter ECS). The Briffa/Osborn perspectives piece points out an important scaling issue that indeed needs further examination. However, to claim as you do that they show that the ECS 40-year low-pass temperature reconstruction is “flawed” begs the question: “flawed” by how much? It is not at all clear that scaling the annually resolved RCS chronology to annually resolved instrumental temperatures first before smoothing is the correct way to do it”

  2. Jimchip Says:

    1051638938 Apr. 29, 2003 Briffa to Cook, Cook quoted:

    I should say that Jan should at least be made aware of this reanalysis of his data. Admittedly, all of the Schweingruber data are in the public domain I believe, so that should not be an issue with those data. I just don’t want to get into an open critique of the Esper data because it would just add fuel to the MBH attack squad. They tend to work in their own somewhat agenda-filled ways. We should also work on this stuff on ourown, but I do not think that we have an agenda per se, other than trying to objectively
    understand what is going on.

  3. Jimchip Says:

    see https://crutapeletters.wordpress.com/section-1-responses/section-1-9-response/#comment-229

  4. Jimchip Says:

    1067005233.txt Osborn reviews Meko to NOAA, claims no COI.

    From: Tim Osborn
    To: evelyn.smith@noaa.gov, “Christopher D Miller”
    Subject: Fwd: confidential assessment of GC04-203
    Date: Fri Oct 24 10:20:33 2003

    Dear Evelyn and Chris,
    re. proposal review GC04-203, Meko et al. “A synthesis of 19th century climate data for the
    United States from paleo, archival and instrumental sources”.
    I have read the “Reviewer conflict of interest and confidentiality…” document and can
    state that I have no conflict of interest and will abide by the confidentiality provisions
    etc.
    I reviewed a very similar proposal by this group 1 year ago, and enclose my review of that
    proposal below. The new proposal has taken into account my two main concerns from last
    time, which were:
    (i) that creation only of a blended data set that contained a time varying mixture of proxy
    and instrumental data would limit the usefulness because its quality would be time varying,
    perhaps in an unquantified way, and independent study of errors between proxy and observed
    data would be prevented; and
    (ii) that the proposed work was not very innovative in terms of the applications for which
    the new information would be used.
    Both of these points have been addressed adequately and so I now rate it “Excellent (5)”
    for scientific/technical merit, and “High (5)” for importance/relevance and applicability.
    One issue that I would like to raise, however, is that the need for quantifying
    uncertainty/error in the reconstructions/database is not given much coverage in the
    proposal. It is mentioned, but not focused on. For many applications (testing models,
    comparison with other reconstructions, detection of unusual climate trends/events),
    explicitly quantified error estimates are essential. These often change magnitude through
    time, and thus should be estimated in such a way as to allow this. They may also change
    with time scale (often being lower for, e.g., a decadal mean than for a single year’s
    value), and again the error estimation method should capture this. I do not think that
    this issue detracts from the quality of the proposal. Instead I am mentioning it in the
    hope that this comment can be passed on to the proposers, in the event that the project is
    funded, so that they can be prompted into placing the appropriate emphasis on quantifying
    uncertainty.
    Apologies for being late yet again, and best regards,
    Tim

    Date: Thu, 24 Oct 2002 17:14:31 +0000
    Subject: confidential assessment of GC03-512
    From: Tim Osborn
    To:
    CC: ,

    Dear Irma and Chris,
    Re. proposal review GC03-512, PI: David Meko “A 19th century data catalog”
    First of all, I confirm that there is no conflict of interest etc.
    Now to my review…
    (1) Scientific Merit
    Rating: Good
    Comments:
    I completely agree with the rationale behind improving data sets of 19th
    century climate (see my comments below on “Relevance to climate change
    programme”), and the proposers have identified the most relevant data
    sources available for the US. The objectives and workplan are generally
    reasonable, but I have rated it “good” rather than “very good” or
    “excellent” because it does not seem as scientifically innovative or
    challenging as it might. Some particular concerns are highlighted below.
    I am very wary about the proposed approach of integrating the data sources
    together to produce a single climate product. Obviously the data sources
    have to be used in combination, for calibration of proxy data or for
    assessment of possibly dubious early instrumental data, *but* combining them
    all into a single product only will be very restrictive for future use,
    assessment, improvements. Much better would be to produce intrumental-only
    series for whatever length is available, and tree-ring only series for the
    full length (i.e., into the late 19th and 20th centuries, despite the
    availability of instrumental data for these periods). Blending them into a
    single analysis is of some, but limited, use and comparisons of different
    periods and with (e.g.) model simulations can only ever be done by taking
    into account error bars that vary dramatically in time and are only
    estimates of the “true” errors – and the error estimates may be
    underestimates if based only on residuals or covariances during the 20th
    century.
    No mention is made of using the 19th century data to consider key issues
    such as difference between tree-ring and ground borehole temperatures (they
    differ more in the 19th century, in terms of trend, than in other
    centuries), possibly taking into account land-use change. No mention is
    made of using the 19th century data to assess multi-century temperature
    reconstructions and why they differ. These are issues of great importance.
    No mention is investigating seasonal dependence of temperature changes,
    which are greater in existing temperature products during the 19th century
    than in the 20th century and which has important implications for the
    calibration of proxy (including tree-ring) data against summer or annual
    data and the need to more clearly define the true seasonal response of proxy
    data.
    Despite these concerns, the proposed work is certainly worthy of funding and
    the extra items of interest that I mention above could be achieved using the
    data generated here, in some future project.
    (2) Relevance to climate change programme
    Rating: High
    Comments:
    The 19th century is certainly of particular importance, not just for the
    reasons outlined in the proposal but also because this century shows some of
    the biggest disagreements in warming trend between various quasi-hemispheric
    temperature reconstructions and between proxy and instrumental data and
    between different seasons of instrumental data. Additional data sources are
    definitely required, and additional digitisation, homogenisation and
    intercomparison of data sets is necessary. For these reasons, work such as
    that proposed here is essential for helping to refine answers to questions
    such as how unusual is late twentieth century climate and detection of
    climate change signals against the noise of natural climate variability.
    Best regards
    Tim

  5. Jimchip Says:

    http://listserv.arizona.edu/cgi-bin/wa?A2=ind1001&L=itrdbfor&D=0&T=0&P=3501

    when correlating ring width chronologies with monthly temperatures with the program Dendroclim, I frequently obtain significant correlation values of below 0.20 (e.g. 0.10-0.17).

    Does anyone know why these low (compared to usual significance thresholds) values are still computed by the program as being significant?

    The answer:
    Martin,

    Dendroclim uses bootstrapped correlation and response functions to
    determine significant values. In the analysis, a correlation may be
    low but still significant. In a single-run correlation analysis using
    Excel, all correlation (high and low) will be shown regardless of
    significance. Check out these two articles by Biondi for details on
    Dendroclim methods.

  6. Jimchip Says:

    Tree rings, GHCN, etc. See also 2.2
    “One of Hansen’s pit bulls, Tamino, has re-visited Mannian principal components.” (heh)

    http://climateaudit.org/2008/03/10/mannian-pca-revisited-1/

    Readers also need to keep in mind that two quite distinct principal component operations are carried out in MBH98 – one on gridded temperature data from CRU; and one on tree ring networks from ITRDB and elsewhere. The characteristics of the networks are very different. The gridded temperature networks result in a matrix of data with some effort at geographic organization, while there is no such attempt in the tree ring networks. The tree ring networks are more like the GHCN station networks than like a gridded network. For comparison, imagine a PC calculation on station data in the GHCN network going prior to 1930 with no attempt at geographic organization or balance. Followers of this discussion realize that long station data is overwhelmingly dominated by U.S. (USHCN) station information. Actually, the tree ring networks are even more disparate than GHCN station networks. Many of the tree ring sites are limited by precipitation. Thus, PC on the tree ring networks is more like doing a PC analysis on a pseudo-GHCN network consisting of mostly of precipitation measurements with some blends of temperature and precipitation, with a predominance of stations from the southwest U.S. There are obviously many issues in trying to transpose Preisendorfer methodology developed for very specific circumstances to this sort of information.

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