date: Fri, 03 Feb 2006 17:04:39 +0000 from: Keith Briffa subject: Fwd: Re: Fwd: new fig to: Tim Osborn >Date: Fri, 3 Feb 2006 09:49:06 -0700 >To: Keith Briffa >From: Jonathan Overpeck >Subject: Re: Fwd: new fig >Cc: Eystein Jansen , t.osborn@uea.ac.uk >X-Virus-Scanned: amavisd-new at email.arizona.edu >X-UEA-Spam-Score: 0.0 >X-UEA-Spam-Level: / >X-UEA-Spam-Flag: NO > >Keith and Tim - I do like what you did, and I >could figure it out. That said, Eystein's >response highlights the importance of my >suggestion to start early on the caption so we >can get it perfect. The presentation is not >intuitive, so we have to educate. BUT, there is >no doubt in my mind that this is more appealing than the FOD approach. > >thanks, peck > >>Eystein >>the shading represents overlaps of the >>uncertainty estimate envelopes surrounding each >>of the 10 reconstructions . If one >>reconstruction curve is envisaged , it has 1 >>and 2 standard error bounds above and below >>each smoothed value. We are trying to represent >>the most likely temperature based on all >>reconstructions. SO if their inner (most likely >>) 1 standard error bands all overlap , we want >>to show a high score . If only the outer >>uncertainty bands overlap between a small >>number of reconstructions, we need to say it is >>unlikely that this is the likely temperature - >>so a small score. Hence we allocate 2 points to >>all areas within the 1 standard error range of >>each reconstruction, and 1 point for the area >>between 1 and 2 standard errors. Then we >>overlap all reconstructions and count the total >>score. They go from maximum (20) WHERE THE PLUS >>AND MINUS 1 STANDARD ERROR Envelopes (i.e. a >>66 percent chance that the "real" value lies in >>this band) OVERLAP FOR ALL RECONSTRUCTIONS >>(each of the possible 10 gets a score of 2 in >>this area) to 0 , where no reconstruction uncertainty envelopes overlap. >>If only the 1 standard error envelopes overlap >>for each of 2 reconstructions , the score is 2, >>and if the inner uncertainty band overlaps with >>the outer uncertainty band of only 1 other >>reconstruction , the score is 3 and so on. >>Hence the high scores show where most >>reconstructions most likely estimate ranges >>overlap. This gives prominence to the middle >>estimate of the most abundant reconstructions, >>and less emphasis on those estimates based on >>only a few or even 1 reconstruction. Hence the >>scores are low where there are few >>reconstructions, and low where the confidence >>in the reconstructions is low. Now you can see >>that the most likely estimates for the MWP are >>lower than those for the recent period - this >>is better than showing the total uncertainty >>range which is controlled by outliers - such as Moberg's curve. >> >> >> >> At 14:40 03/02/2006, you wrote: >>>Hi Keith, could you just explain the values >>>reflecting the colour shading n the lower panel? >>>Eystein >>> >>>>Peck and Eystein >>>>we are having trouble to express the real >>>>message of the reconstructions - being >>>>scientifically sound in representing >>>>uncertainty , while still getting the crux of >>>>the information across clearly. It is not >>>>right to ignore uncertainty, but expressing >>>>this merely in an arbitrary way (and as a >>>>total range as before) allows the uncertainty >>>>to swamp the magnitude of the changes through >>>>time . We have settled on this version >>>>(attached) of the Figure which we hoe you >>>>will agree gets the message over but with the >>>>rigor required for such an important document. >>>> >>>>We have added a box to show the "probability >>>>surface" for the most likely estimate of past >>>>temperatures based on all published data. By >>>>overlapping all reconstructions and giving a >>>>score of 2 to all areas within the 1 standard >>>>error range of the estimates for each >>>>reconstruction , and a score of 1 for the >>>>area between 1 and 2 standard errors, you >>>>build up a composite picture of the most >>>>likely or "concensus" path that temperatures >>>>took over the last 1200 years (note - now >>>>with a linear time axis). This still shows >>>>the outlier ranges , preserving all the >>>>information, but you see the central most >>>>likely area well , and the comparison of past >>>>and recent temperature levels is not as >>>>influenced by the outlier estimates. What do >>>>you think? We have experimented with >>>>different versions of the shading and this >>>>one shows up quite well - but we may have to >>>>use some all grey version as the background >>>>to the overlay of the model results. >>>>We have also experimented with changing the >>>>normalisation base for the >>>>model/reconstruction Figure , but using the >>>>same short modern period as for the first >>>>Figure is not satisfactory - more on this >>>>later. We have added in Oerlemans curve as >>>>many insisted - but we only have the GLOBAL >>>>curve - can you get the separate North and >>>>Southern Hemisphere curves (with uncertainty) >>>>. I do not see that the new model runs from >>>>Germany/Switzerland will fit easily in the >>>>existing Figure and need to be separate! I am >>>>really struggling with the text also - really need more time!!!! More later >>>>Keith >>>> >>>>>X-Mailer: QUALCOMM Windows Eudora Version 7.0.0.16 >>>>>Date: Fri, 03 Feb 2006 10:42:15 +0000 >>>>>To: Keith Briffa >>>>>From: Tim Osborn >>>>>Subject: new fig >>>>> >>>>> >>>>> >>>>> >>>>>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 >>>> >>>>-- >>>>Professor Keith Briffa, >>>>Climatic Research Unit >>>>University of East Anglia >>>>Norwich, NR4 7TJ, U.K. >>>> >>>>Phone: +44-1603-593909 >>>>Fax: +44-1603-507784 >>>> >>>>http://www.cru.uea.ac.uk/cru/people/briffa/ >>>> >>>>Attachment converted: Nebbiolo:ipcc_nhrecon_new1.pdf (PDF /«IC») (00A6614D) >>> >>> >>>-- >>>______________________________________________________________ >>>Eystein Jansen >>>Professor/Director >>>Bjerknes Centre for Climate Research and >>>Dep. of Earth Science, Univ. of Bergen >>>Allégaten 55 >>>N-5007 Bergen >>>NORWAY >>>e-mail: eystein.jansen@geo.uib.no >>>Phone: +47-55-583491 - Home: +47-55-910661 >>>Fax: +47-55-584330 >> >>-- >>Professor Keith Briffa, >>Climatic Research Unit >>University of East Anglia >>Norwich, NR4 7TJ, U.K. >> >>Phone: +44-1603-593909 >>Fax: +44-1603-507784 >> >>http://www.cru.uea.ac.uk/cru/people/briffa/ > > >-- >Jonathan T. Overpeck >Director, Institute for the Study of Planet Earth >Professor, Department of Geosciences >Professor, Department of Atmospheric Sciences > >Mail and Fedex Address: > >Institute for the Study of Planet Earth >715 N. Park Ave. 2nd Floor >University of Arizona >Tucson, AZ 85721 >direct tel: +1 520 622-9065 >fax: +1 520 792-8795 >http://www.geo.arizona.edu/ >http://www.ispe.arizona.edu/ -- Professor Keith Briffa, Climatic Research Unit University of East Anglia Norwich, NR4 7TJ, U.K. Phone: +44-1603-593909 Fax: +44-1603-507784 http://www.cru.uea.ac.uk/cru/people/briffa/