cc: Eystein Jansen ,rahmstorf@pik-potsdam.de, drind@giss.nasa.gov,FortunatJoos@email.arizona.edu date: Thu, 13 Jan 2005 16:19:31 +0000 from: Tim Osborn subject: Re: Need your help on something important to: Jonathan Overpeck ,Keith Briffa At 23:50 12/01/2005, Jonathan Overpeck wrote: >Toward that end, I wonder if you two (or maybe just Tim if Keith is >working more on 6.3.2.1) could read and comment/edit on: > >Section 6.4.3.2 -evaluation of transient model runs of the last millennium > >and > >Section 6.5.8 - synthesis of climate sensitivity issues > >Eystein and I are asking that you do this FAST because these sections must >be compatible with your section 6.3.2.1 (and because you guys know as much >as any about the material in these two other sections!). Dear Peck (plus cc to others - have I sent it to the appropriate people?), Keith and I have looked at these sections and the attached documents contain my tracked changes. They seem to be compatible with Keith's section and the figures. We've put in a couple of simple cross-references to the figures from Keith's section. Plus some minor changes. Plus some comments, particularly about the section(d) of the climate sensitivity section. Keith expands upon these latter comments with the following: -------------------- It would be wise NOT to refer to the Maunder Minimum time period. Anyway, 1675-1715 is (by most opinions) the LATE Maunder Minimum (an accidental name that derives from the random non-availability of documentary/paleo data for the earlier part of the period in some [Swiss] study by Pfister and people). Up to then, MM was taken to be 1645/50 to 1715. By using this terminology you divert objective analysis of TOTAL forcing change (particularly given volcanic uncertainty). The definition of "today" is also crucial as it affects (albeit not precise) estimation of forcing changes from the earlier period. The wider the comparison base, the more imprecise the estimates. The narrower the base, the more you could argue about likely non-equilibrium (see Tim's comment in attached document). The volcanic forcing likely means that the LMM is likely not in equilibrium either! Nice if base period for estimates of changes (forcings and temperatures) could be compatible with the base period used in Figure 1). We will cross reference this section from ours. -------------------- Cheers Tim and Keith Attachment Converted: "c:\eudora\attach\6.4.3.2_osborncomments.doc" Attachment Converted: "c:\eudora\attach\6.5.8_osborncomments.doc" Dr Timothy J Osborn Climatic Research Unit School of Environmental Sciences, University of East Anglia Norwich NR4 7TJ, UK e-mail: t.osborn@uea.ac.uk phone: +44 1603 592089 fax: +44 1603 507784 web: http://www.cru.uea.ac.uk/~timo/ sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm