cc: Martin.Manning@noaa.gov, Susan Solomon , Matilde Rusticucci , Phil Jones , Peter Lemke , Jurgen Willebrand , Nathan Bindoff , zhenlin chen , Melinda Marquis date: Tue, 09 Jan 2007 09:09:43 -0700 from: Kevin Trenberth subject: Re: IPCC WG1 Observations Conference Call to: Brian Hoskins Hi all Attached is a new version of the proposed ppt on obs. I have included a different version of the global mean temperature curve with just one trend line on it: see if you think the message related to that is the right one; and the one with all the trtend lines is hidden in reserve. I now have just 1 hurricane slide with 2 in reserve. I also had some fun with the last slide, following Susan's suggestion (that I am sure she did not intend me to follow up on). Make sure you play that with slide show turned on. Anyway the bottom line is that without the last slide there are now 22 slides, and 8 and 9 essentially count as 1 (or leave 9 out), so it would be order 22 minutes. I could remove a slide like slide 20 but then I would have to take extra time on the previous slide to explain, and so I don't think much would be gained. Slide 18 would be short and acts as a segue to drought. Jurgen, should I add your slides to this? Do you want to change them, maybe to have a similar format, with a header that has the main message? Peter, do you also want me to add yours? Cheers Kevin Brian Hoskins wrote: > Dear All > > I kept quiet over the discussion about trend lines as I think the > final result of not putting them on the 3 curves in the SPM is the > right one. However I certainly defend the use of the 25, 50,100, 150 > year trend lines on the temperature curve as in the TS and Chapter 3 > as being better than the alternatives. A linear fit may not be a good > one but when one is trying to make the smallest number of assumptions > it is more defensible than for example putting in seemingly arbitrary > break-points. The picture also gives a visual impression of how > representative the average rates of change numbers are.The fact that > the trend lines for different time-wondows are all different itself > shows that the linear fit is not good for the longer time-scales. The > monotonically increasing slopes as one moves from the longer to the > shorter time-scales is a strong indication of acceleration, but I > would not put this in the same sentence as the word "unequivocal". > > Best wishes > > Brian > -- **************** Kevin E. Trenberth e-mail: trenbert@ucar.edu Climate Analysis Section, www.cgd.ucar.edu/cas/trenbert.html NCAR P. O. Box 3000, (303) 497 1318 Boulder, CO 80307 (303) 497 1333 (fax) Street address: 1850 Table Mesa Drive, Boulder, CO 80305 Attachment Converted: "c:\eudora\attach\C3IPCCParis2.ppt"