Wednesday, March 14, 2012

2482.txt

cc: Tim Osborn <t.osbornatXYZxyz.ac.uk>, Keith Briffa <k.briffaatXYZxyz.ac.uk>, Ed Cook <drdendroatXYZxyzo.columbia.edu>
date: Mon, 18 Jun 2001 17:24:45 -0400
from: "Jonathan M. Adams" <jmadamsatXYZxyzl.uri.edu>
subject: Re: possible reconstruction of climate transfer functionsfromtree
to: Ed Cook <drdendroatXYZxyzo.columbia.edu>

Hi Ed,

Good to hear that you are interested! The approach I'm proposing using
a MANN (modular artificial neural network) model should be ideal for
coping with the difficulties you point out. The model seeks out clusters
that may be associated with a particular set of soil conditions, a
local/regional genotype, a particular local/regional custom of tree
treatment such as pollarding, or whatever.

I am just starting writing the idea down as a proposal and will send
you a draft in the next couple of days. As I don't know much about
dendrochronology, it is bound to be full of mistakes so I'll appreciate
your patience in correcting what I write.


Best regards,

Jonathan


Ed Cook wrote:
>
> Hi Jonathan,
>
> I would love to work on this project with you, Keith, and Tim. Let's see
> what we can do to pull it together. It is not without its difficulties, in
> part related to the fact that tree-ring chronologies of different species
> growing under the same regimes of climate, soil, etc. may lead to
> distinctly different neural network models due to different intrinsic
> biological/genetic responses to the same forcings. Maybe this is what we
> are looking for.
>
> Ed
>
> >Ed, I've been in touch with Keith Briffa and Tim Osborne at UEA, and
> >they are very interested in this neural network approach (am cc-ing this
> >note to Tim). I am now thinking that it would be good to have a proposal
> >involving yourself, the UEA people, and us folks at URI to look at tree
> >rings in relation to a range of GIS layers such as soils as well as
> >annual climate etc.. I might also need to bring in someone at PennState
> >who is a real whizz at assembling data layers for GIS. Since the total
> >for the project must not exceed $250,000, we'd all have to be working
> >part time on this (I don't think there is enough to fund anyone full
> >time).
> >
> >The type of model I have in mind, a MANN model, looks for and finds
> >regional clusters of relatively uniform behaviour, and then does a
> >separate neural network analysis for each of the clusters it finds. It
> >would be just ideal for the tree ring data.
> >
> >I don't think computing capacity will be a problem. My colleague YQ Wang
> >(who is the real neural net programmer in this) assures me this is well
> >within the capacity of the computers in the GIS group here. I think we'd
> >need to do separate model runs for the USA, Canada and Europe using
> >whatever environmental GIS layers are available for each area.
> >
> >
> > Jonathan
> >
> >
> >
> >
> >> Artificial neural networks have been used to estimate climate from tree
> >> rings by a few people like Connie Woodhouse and Joel Guiot. This approach
> >> certainly has considerable promise when there are unknown or ill-specified
> >> nonlinearities in the "true" model. As far as I know, no one has tried to
> >> use GIS info to try to develop a regional model of tree ring widths using
> >> neural networks. This is an interesting topic. Whether or not it is too
> >> computationally demanding to do on a large regional scale is hard to say.
>
> ==================================
> Dr. Edward R. Cook
> Doherty Senior Scholar
> Tree-Ring Laboratory
> Lamont-Doherty Earth Observatory
> Palisades, New York 10964 USA
> Email: drdendroatXYZxyzo.columbia.edu
> Phone: 845-365-8618
> Fax: 845-365-8152
> ==================================

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