cc: Keith date: Fri, 31 Mar 2006 14:57:01 +0100 from: Tom Melvin subject: Re: 1750-present temperature reconstruction to: "Rob Wilson" Rob, We have been working on a northern Eurasia reconstruction which is being drafted. Keith wants to publish a review of the sensitivity problem and again it is in the drafting stage. Hopefully both will ready to submit by the end of April. Both papers partly depend on procedures from my thesis (and subsequent developments) and depend on us also publishing descriptions of these new methods and the programs (or procedures) and several documents are being developed. Until the definitive reconstructions are ready i.e. the ones used in the papers we do not have new temperature reconstructions to give you. The programs you enquired about earlier are still not in a state for general release. Some are Fortran procedures but not suitable to use as a "black box" due to arbitrary slope problems. A problem with reconstruction using samples from living trees is overcoming the segment length curse and, because of this, the sensitivity loss is not proven or demonstrated by most of the papers discussing the sensitivity issue. The problem of selecting data that shows no sensitivity loss becomes one of selecting a processing method capable of demonstrating such loss. The Scandinavian sites (mine to 1997 and 2000, and Keiths to 198? ) are on ITRDB, as raw measures which cover the 1750 onwards period if you wish to use them. I have some pith estimates. Thanks for the Dawson temperature data. It looked different to our data (CRU dataset) but the problem appears to be that the US data and Canadian data have been differently homogenised. Examining the sensitivity problem at TTHH may best involve RCS type methods (but needs sub-fossil data and pith estimates for "heart rot" trees). Also care will be needed because the mean ring width of the update chronology (with rings after 1976) appears 20% lower than that of the original trees over their common period. An Alaskan earthquake in which Dawson and surrounding tree sites sink into the ocean, but backdated by a century, might remove these current problems! Tom Melvin At 16:34 13/03/2006, you wrote: >Hi Tom [and Keith], >I am mulling over an idea of developing a completely independent NH >temperature reconstruction using relatively short data-sets to >compare with existing NH recons. > >I am focusing on the 1750-present period ONLY. > >I was wondering if you have any data (recons) from Scandinavia that >would be relevant to this exercise. > >I am only interested with data that show NO sensitivity loss in the >recent period. > >Pickings are surprisingly meagre. Of published temperature >reconstructions that go into the 1990s, I have my work from BC >(Canada), Buentgen's recons from the Alps, and a recon from >Kamchatka by Greg Wiles. > >Brian may have new data from the Yukon, and there are some >interesting new data-sets from Japan. > >However, I have not yet looked at the Scandinavian region. >I know your data have been submitted to the ITRDB, but if you have >any specific reconstructions, that would make my life much easier. > >it is only an idea at the moment, but this may parallel work that >Keith is currently doing addressing the sensitivity issue. > >hope you can help >regards >Rob >----------------------------------------------------------------------- >Dr. Rob Wilson >Research Fellow >School of GeoSciences, >Grant Institute, >Edinburgh University, >West Mains Road, >Edinburgh EH9 3JW, >Scotland, U.K. >Tel: 01968 670752 > >Publication List: >http://freespace.virgin.net/rob.dendro/Publications.html > >".....I have wondered about trees. > >They are sensitive to light, to moisture, to wind, to pressure. >Sensitivity implies sensation. Might a man feel into the soul of a tree >for these sensations? If a tree were capable of awareness, this faculty >might prove useful. " > >"The Miracle Workers" by Jack Vance >----------------------------------------------------------------------- Tom Melvin Climatic Research Unit University of East Anglia, Norwich, NR4 7TJ, U.K. Phone: +44-1603-593161 Fax: +44-1603-507784