From	GIORGI FILIPPO	Date	Mon, 11 Sep 2000 16:58:02 +0200 (MET DST)
To	Chapter 10 LAs -- Congbin Fu, GIORGI FILIPPO, Bruce Hewitson, Mike Hulme, Jens Christensen, Linda Mearns, Richard Jones, Hans von Storch, Peter Whetton
Subject	On "what to do?"
Dear All we heard the opinions of most LAs, namely Jens, Richard, Linda, Peter, and Hans as well as some interesting interpretations of my email (Linda says: " You seem to be assuming that the most desirable result is if the SRES results have no contrasts with the IS92a results. I don't understand your reasoning on this." I do not have any particular desire on the new data. We said that one thing to look at was the agreement with the old data and thus I noticed that relaxing the criteria would yield a greater agreement). I would say that a broad range of opinions was covered, from one where the SRES should essentially be commented upon concerning their agreement with the old data to one in which all the old stuff should be replaced with SRES stuff. Some people want to make the BOX more central, others want to get rid of it. Given this, I would like to add my own opinion developed through the weekend. First let me say that in general, as my own opinion, I feel rather unconfortable about using not only unpublished but also un reviewed material as the backbone of our conclusions (or any conclusions). I realize that chapter 9 is including SRES stuff, and thus we can and need to do that too, but the fact is that in doing so the rules of IPCC have been softened to the point that in this way the IPCC is not any more an assessment of published science (which is its proclaimed goal) but production of results. The softened condition that the models themself have to be published does not even apply because the Japanese model for example is very different from the published one which gave results not even close to the actual outlier version (in the old dataset the CCC model was the outlier). Essentially, I feel that at this point there are very little rules and almost anything goes. I think this will set a dangerous precedent which might mine the IPCC credibility, and I am a bit unconfortable that now nearly everybody seems to think that it is just ok to do this. Anyways, this is only my opinion for what it is worth. Going to the problem at hand, I have a proposal that is in between the two extreme positions. I think the SRES runs should be included and highlighted in the chapter, but should not be the only source of our conclusions, partially also for the reasons I state above (I seem to remember that in Chapter 9 the SRES results were only a small section in the whole chapter in which it was said that they essentially confirmed previous findings). Also let me say that, as it currently stands, the box is essentially meaningless, because it simply repeats what is already said in the executive summary. With these premises here is my proposal: 1) We leave 10.3 more or less as it is, a discussion of published science on model behavior, uncertainty, some climate change runs. Perhaps we shorten it or something like that. I am not in favor of presenting Giorgi and Francisco-type plots for the SRES runs for the simple reason that they do not convey effectively what readers want. Proof is that we had all the plots there and we were accused of not having any results in the chapter !! I think people want something more direct, i.e. plots similar to the +/- one we had proposed in the BOX. 2) We make the BOX only with SRES results, i.e. the BOX becomes a summary presentation of the SRES projections. In this way we accomplish several objectives: we highlight the SRES results in a way that is of direct impact (after all this is what working group II people are really interested in); we can explicitly state that the results are preliminary and sort of differentiate them from the more IPCC-proper chapter material (of course we are not going to say so); we have a natural place for the BOX (end of 10.3), do not need to rewrite the whole thing and just need to make the proper connections with the rest of the chapter. All and all I think this is a feasible and clean solution. The rest of the material in the old box (sections a and c) was really just general material repetitive of what we were saying in various other part of the chapter. 3) In the executive summary we summarize what we believe are the confident patterns from the combination of old and new runs. As to what should the SRES box look like. I hear people liked a lot our +/- plot, so we do the same types of plots, both for precip and temperature, one for the A2 and one for B2 scenarios, plus one or two paragraphs explaining the plots. This will portray agreement not only across models but also across what are now considered plausible scenarios. We can easily fit 4 plots in a page and if need be fit the 1-2 paragraphs on another page (I do not see anything wrong with a 1.5 page box). For precipitation I think the old criteria are fine. For temperature this is what I propose. In the precip plots we had 4 sub-categories, (+, - large change, small change) plus the inconclusive, or whatever we decided to call it. Similarly, we could do 4 categories here 1) Amplification positive, 2) Amplification negative (i.e. less than the global average), 3) strong amplification (> 50%), 4) small amplification (between 25 and 50 %). I cannot visualize it at the moment, but I think this will work to figures analogous to the precip ones. Correct me if I am wrong. To the two technical issues: 1) Do we soften our requirement, i.e. from n-1 to n-2 model agreement? I do not feel strongly about it but am more in favor of not softening the criterion. We are looking for confidence and model agreement and should have stringent requirements on it. 2) Do we include the outliers in the analysis? I say yes, not having time for more detailed analysis as to why they should not be included. In Chapter 9 they are presented as bracketing the answers not as being wrong. This is the problem of not having published research on this. perhaps a paper would have excluded them on scientific grounds, but can we at this point? I am not sure we can have solid enough foundations to legitimate it. Besides, I have done analysis without them as well and things did not change almost at all. To the operational issues: 1) I agree there is no time for a paper to be delivered before the Sept. 26 deadline. After the deadline however, and with some calm, I think we should have a paper on it. 2) Meeting or conference call. I myself am not keen on a meeting of the Europeans. Jens is not back until the end of the week, which means the meeting would have to be during the last week before deadline. With all that is still left to do on the chapter and other internal committments I have, I certainly could do without spending 2 days to do this (which is always the minimum it takes me to get anywhere and back)and I cannot do it over the weekend since I am not here. It sounds like we would have to contact people by phone anyways (see Peter and Linda's messages), so why not a conference call directly? >From the technical viewpoint Linda seems to be the best person to organize this. As soon as Jens is back perhaps? (Jens if you can read this can you let us know when this is possible?). 3) We just got the MPI data and the full CCC ones (I guess some was lost in the previous run). We need to incorporate these so we have all models available. I and Bruce will interact on this. 4) I agree we should contact the TSU about it, but I also think we should have a proposal on it with less spread than current to present them. Last but not least, please work on your section revisions (especially those who have nothing to do with the BOX) so at least we get that out of the way. Cheers, Filippo ################################################################ # Filippo Giorgi, Senior Scientist and Head, # # Physics of Weather and Climate Section # # The Abdus Salam International Centre for Theoretical Physics # # P.O. BOX 586, (Strada Costiera 11 for courier mail) # # 34100 Trieste, ITALY # # Phone: + 39 040 2240 425 # # Fax: + 39 040 2240 449 (or + 39 040 224 163) # # email: giorgi@ictp.trieste.it # ################################################################