cc: peterwthorne@btinternet.com
date: Fri Feb  4 13:21:56 2005
from: Phil Jones <p.jones@uea.ac.uk>
subject: Re: [Ch3-cas] [Fwd: Zero order draft of Chapter 3, AR4, IPCC]
to: "Thorne, Peter" <peter.thorne@metoffice.gov.uk>, Kevin Trenberth <trenbert@cgd.ucar.edu>, Chris Folland <chris.folland@metoffice.com>, Simon Tett <simon.tett@metoffice.com>, David Parker <david.parker@metoffice.com>

    Peter,
        Neither Kevin (I think) nor I have yet seen the CCSP draft. I have just
    received it as I've agreed to be on the review panel. Eventually, Ch 3
    will have to somewhat agree with CCSP, but you are looking at the
    ZOD. We have the FOD, SOD and maybe a TOD to go through yet.
       If the CCSP comes out before the FOD commenting period then
    we will likely get loads of comments coming in telling us the same
    thing, so the FOD is likely to markedly different from the ZOD.
       Thanks for your comments - they are almost the first. Kevin has
    forwarded a somewhat similar broadside from John Christy - with detailed
    comments to follow, when he has time to catch breath.
      So, take it from me the FOD will be a marked improvement on the ZOD
    - not just in this section, but in almost all sections. Some sections
    need a lot more work than this one. Remember that responding to
    comments is the purpose of the reviewing strategy !
      I'll own up to writing CQ 3.2 !  I did it in 30 mins a few weeks ago. It is
    better than the text provided by one of CA's, but it needs a lot of more
    work - something I didn't have time for in early Jan. It may only be
    better in the sense that it does mention vertical temperature trends !
      If you're there on Feb 22 (in the delightful O'Hare Hilton) then we can
    discuss this further. I should have read the CCSP by then !
    Cheers
    Phil

   At 10:57 04/02/2005, Thorne, Peter wrote:

     Kevin, Phil et al.,
     my substantive comments on the upper-air portion only. Before I give
     specific comments below I have some over-arching comments:
     This draft and the CCSP report seem at best tangential - is this
     desirable or sensible?
     There is little effective communication in the main text of the
     uncertainty that is inherent in these measures due to the poor quality
     of the underlying data and metadata and to the choices made -
     "structural uncertainty". It seems that a decision has been made that
     RSS and the Fu et al. method are "right" or at least "most right" and
     this is what we will put forward as gospel truth almost. Other datasets
     are given a cursory once over almost. This completely ignores legitimate
     concerns that "structural uncertainty" is large aloft - seemingly
     reasonable choices made as to how you homogenise and then analyse the
     data can have very large effects. This is not at all clearly
     communicated in the current draft.
     The essential distilled message that I think the analysis of UA
     temperatures has left us since the TAR, and what this chapter should
     say, is:
     "Independent efforts to create climate records from satellite and
     radiosonde records since the TAR have served to illuminate previously
     unrecognised uncertainties in temperature evolution aloft (Seidel et
     al., 2004, Thorne et al., 2005). Further, choices in post-processing
     (e.g. Fu et al., 2004)  may help to clarify satellite retrievals, but
     legitimate concerns remain (Thorne and Tett, 2004, Spencer et al., 2005)
     and other equally plausible approaches should be actively considered.
     Our increased understanding of trend uncertainty aloft means that we can
     no longer dismiss warming aloft of similar or greater magnitude than at
     the surface over the satellite record. Nor can we discount a relative
     cooling aloft. Uncertainties are largest in the tropics and Southern
     Hemisphere high latitudes where radiosonde coverage is poorest.
     Obviously, the climate has only evolved along a single pathway.
     Therefore a major challenge to the climate community is to refine our
     range of estimates."
     This is what CCSP effectively says.
     What, rightly or wrongly, I get out of the current draft on an initial
     read is:
     "We don't like UAH. We don't believe radiosondes over the satellite
     period, but do over the longer period (paradox). We believe Fu et al. is
     correct. There is no longer any problem whatsoever."
     I don't think this simple message is actually remotely supported by the
     science. Therefore at the very least efforts are required to balance the
     text so that this is not the message communicated. I don't think we
     should be scared of admitting that we just don't know, if indeed we just
     don't know (which I believe is a fair reflection of the state of the
     science).
     Specific comments:
     p.23 lines 13-14 and 53-57 and p.24 lines 1-6. I disagree strongly with
     these as written. I do not believe that Fu et al. weightings is some
     panacea nor that the "cancellation" works on all space and timescales
     (the statement needs to be *proved* it cannot be accepted as an article
     of faith - that is not the way science works). I'd be amazed if it did.
     The reservations raised in the peer reviewed literature need to be
     better articulated here for the document to be fair and balanced. I
     guess this whole area will evolve significantly over the next 12 months
     or so though.
     General concern: In the TAR we used 20N to 20S to define the tropics -
     here (Table 3.4.1.b) you use 30N to 30S. I'd suggest 20-20 is physically
     more logical and has backward compatablity and should be used. This is a
     recommendation of the Exeter workshop report queued for review in BAMS.
     Regardless, you need to alight on a single definition of these regions
     here and elsewhere in the report and stick to it. If you look at zonal
     mean profiles from any UA dataset then 20-20 shows marked trend changes
     N and S of it (greater warming) so using 30-30 gives a chance of a fools
     gold scenario arising.
     In Table 3.4.1.b TLT is the acronym used in Christy et al. 2003 for T2LT
     - this may very well cause confusion. Admittedly I was only scanning the
     tables but I thought that this claimed there was a RSS 2LT channel
     equivalent!
     Page 26 lines 28-37. This is at significant odds with the CCSP report
     conclusions as currently written. Much of this relates to the relative
     weighting being given to the Fu et al. approach by the different author
     teams. It will seem very odd to a policy maker to read two such
     disparate threads. I particularly dislike the use on line 30 of "when
     the stratospheric influence is properly taken into account (Fu et al.,
     2004a)". How can we say it is properly taken into account that way?
     There are a very large population of plausible approaches that could be
     taken and to date we have two - a "physical" 2LT and a statistical
     T850-300. That is grossly insufficient to make bold statements regarding
     one of them properly taking the effect into account. Again, this needs
     balance and caveats on the Fu et al. technique until we resolve
     unanswered questions. Likewise, T2LT has not been proven to be untenable
     in the peer reviewed press - so you cannot make this statement. My
     feeling is that we are missing a significant opportunity here to outline
     the considerable uncertainty in evolution aloft in favour of deciding
     one subset of approaches is right and presenting this as gospel truth. I
     am very uncomfortable with this. As I said it is at significant odds
     with CCSP.
     page 26. para starting on line 46. Seems almost an afterthought. For
     HadAT (at least, but as they are so highly correlated, also highly
     likely LKS) the long-term trend in the tropics is entirely an artifact
     of the regime shift - if you split time periods then pre- and post-1979
     have negative trends and the whole period has a strong positive trend.
     So to state boldly that trends agree and therefore all is well is again
     our living in a fools paradise. It is true, but it just shows that trend
     metrics are very dangerous beasties and should be handled with care. The
     Seidel and lanzante paper should also be quoted here.
     page 68. Bullets on line 15, line 19, and line 31. Again, my concern
     here is that these are far too narrow and you are effectively claiming
     that one approach is right. Really refers back to my earlier points.
     This is painting a light fuzzy grey as black when I don't believe the
     science to date supports such an interpretation.
     Page 110, line 55. Containing 676 stations (not CDRs).
     Page 111, line 31 The Thorne et al. referenced is a paper under review
     at BAMS that you don't have in your current reference list. Reference
     is: Causes of differences in observed climate trends Peter W. Thorne,
     David E. Parker, John R. Christy, Carl A. Mears

     Common question 3.2. You'll be unsurprised to hear that I think this
     paints too rosy a picture of our understanding the vertical structure of
     temperature changes. Observations do not show rising temperatures
     throughout the tropical troposphere unless you accept one single study
     and approach and discount a wealth of others. This is just downright
     dangerous. We need to communicate the uncertainty and be honest.
     Phil, hopefully we can find time to discuss these further if necessary
     either in Chicago or when I visit in March (has a date been decided
     yet?).
     I'll be away from three weeks from today and unable to access this email
     account. If we need to iterate further I can be reached (intermittently)
     on peterwthorne@btinternet.com but will be fairly busy and then on
     holiday in the middle week.
     Peter
     --
     Peter Thorne     Climate Research Scientist
     Hadley Centre for climate prediction and research
     Met Office, FitzRoy Road, Exeter, EX1 3PB
     Tel:+44 1392 886552 Fax:+44 1392 885681 [1]http://www.hadobs.org

   Prof. Phil Jones
   Climatic Research Unit        Telephone +44 (0) 1603 592090
   School of Environmental Sciences    Fax +44 (0) 1603 507784
   University of East Anglia
   Norwich                          Email    p.jones@uea.ac.uk
   NR4 7TJ
   UK
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