cc: rjwilson@julian.uwo.ca date: Mon, 27 Sep 1999 12:39:40 -0400 from: Brian Luckman subject: Re: northern network(s) to: Keith Briffa Greetings Keith You may find the attachment of interest. Keep me updated on this. Unfortunately I am rather preoccupied just now with my daughter's wedding next week. We have 6 new density chronologies from high elevation in southern BC and a reconstruction back to 1600 which follows the Icefields curve but also has problems in the late 20th century in modelling temperature increase- but the problem apppears to be ringwidth ( more anon) I have forwarded your message to Glen Any movement on the Precip reconstruction paper? Cheers Brian t 04:37 PM 9/27/1999 +0100, you wrote: >>27 September 1999 >> >>Hi >> >>I thought it worthwhile to mention an idea that I, and Fritz Schweingruber, >>have been considering for a while: namely the need to update the circum >Arctic >>network of tree-ring chronologies. >> >>All of you have strong research interests in northern boreal forest and it >>seems to me that we might all share a mutual interest and benefit from >>discussing the options on how to achieve this. Our own work, as you know, >>indicates a puzzling drift in the decadal timescale correspondence between >>falling density values and rising summer temperatures, most apparent in >the 30 >>years leading up to the 1980s. This is juxtaposed with a longer rising >trend >>in basal areas, apparent from around the middle of the 19th century, but >which >>seems to have largely stabilized again in the later part of the current >>century. What are believed to be unprecedented levels of global warmth >(let's >>say in a 1000-year context) are manifest in the last decade or so (though >the >>details of high latitude warming are open to discussion). This fact alone >>demands that we explore the nature of tree-growth/climate responses in >>recent decades as extensively as possible. The opportunity to explore >>time-dependent growth responses and validate previously calibrated transfer >>functions against certainly unusual background conditions (i.e. increased >>anthropogenic influence) all point to an urgent need to update our mutual >>growth data. The work 'mutual' might bring a wry smile to some faces as >it is >>also clear that we have all, for the most part, followed our individual >>dendroclimatic paths up until now! >> >>This brings me to the CAPE (Circum Arctic Palaeo Environments) project: >though >>in principle this incorporates a high-resolution component, in practise it >has >>not, for whatever reason, had any meaningful focus on, or given much >direction >>to, high-resolution (read especially dendroclimatic) research. >> >>I do not know what all of your most recent priorities are, but for our part >>(Fritz, myself, and hopefully Stepan and Eugene) we see the need to continue >>development of a circum Arctic tree-ring (densitometric) network and a >need to >>improve and update major parts of it. Presumably, many of you think >likewise, >>even if your own interests do not directly revolve around tree-ring-density >>data. In the next few months, I (and a number of the addressees of this >>message) will be planning an approach to the European Community to support >>work that might enable us to achieve some of this in Europe and Siberia. We >>are also considering how this might also best be done in the U.S. and >Canada. >>Also, what about somewhat more southerly (but strongly temperature >>sensitive) regions such as western U.S., Tibet, European Alps and Mongolia? >>Is it time to consider a combination of our resources or some form of >>coordinated approach to multiple funders? We have different approaches, >>opinions, geographical priorities, etc. etc. However, there are surely >>scientific and practical advantages in considering a more integrated >future. >>The Canadian government, the new PARCs initiative and existing NSF funding >>sources could probably all be tapped by many of you in N. America. As I >said, >>we will be approaching the EC. What about considering linked proposals? >What >>are the data exchange implications? Would some of you with densitometric >>equipment be willing to collaborate with Fritz and Eugene in updating >>some sites (Eurasian or N. American or whatever) and exploring recent >>(potentially age-dependent) changes in densitometric responses across the >>network? The development of longer (Holocene) records of tree-growth >>and tree-line change would surely benefit from closer collaboration across >and >>between continents. I throw this out to see what you think. >> >BY THE WAY - > > I just sent this to people whose addresses I had to hand - e.g. I could >not find an address for Glen McDonald- and you may think others would be >interested, so feel free to forward it if you think it appropriate. > > >>the best to all, >> >>Keith Briffa > >-- >Dr. Keith Briffa, Climatic Research Unit, University of East Anglia, >Norwich, NR4 7TJ, United Kingdom >Phone: +44-1603-592090 Fax: +44-1603-507784 > Attachment Converted: "c:\eudora\attach\SYNOPSIS ( with colour diagram).doc"