Sunday, May 6, 2012

3849.txt

date: Mon Dec 15 14:17:34 2008
from: Tom Melvin <t.m.melvinatXYZxyz.ac.uk>
subject: Re: NERC proposal
to: Martin Wilmking <wilmkingatXYZxyz-greifswald.de>

Martin,
I would start by separating trees detrended with horizontal line from the others. Then try
signal-free method. Should produce slight improvement but each chronology will have an
"unknown" overall slope.
Then try RCS method, but hopefuly with sufficient trees to use multiple RCS curves (for
separate growth rate classes of tree) and see what resuls are like. Can group trees with a
common signal when building RCS curves.
Can you send me what data you have? I would only use it with your permission.
Tom
At 14:01 15/12/2008, you wrote:

Tom,
great if you could run the data!
In the data I collected there is some pith offset (which we could "correct"), but since
we are also using data collected by a colleague who worked at the same site and I dont
know the offset, maybe it would be best to only test the traditional version?
Martin
PS I am ccing Dr. Jayendra Singh, who is currently working on the data
Tom Melvin wrote:

Martin,
Yes.
I am currently amending program but should be able to run the data through signal-free
method, both curve-fitting and RCS.
Hopefully programs will be sufficiently developed soon (with help and documentation) for
you to be able to use them.
Do you have any missing pith offset data for the sites. For "modern" chronologies it can
make a significant difference to RCS.
Tom
At 13:20 15/12/2008, you wrote:

Dear Tom,
thanks for the copy!
Dear Keith, get well soon.
Martin
btw, Tom, we have a data set from eastern Alaska, where we do have massive change in
temp sensitivity (about 90% of sampled trees), if we detrend traditionally or with RCS.
Would it be possible for you to test this data set with your signal free approach, since
it seems as if the Canadian sites (Mackenzie Delta) close by are affected by
standardization method?
thanks
martin
Melvin wrote:

Martin,
Attached is a copy of the proposal that we submitted and an explanatory letter from
Keith (who is sick with flu at the moment).
Tom Dr. Tom Melvin
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Phone: +44-1603-593161
Fax: +44-1603-507784

--
Martin Wilmking, Ph.D.
Working Group: Ecosystem Dynamic
Institute for Botany and Landscape Ecology
University Greifswald Grimmer Strasse 88 D - 17487 Greifswald, Germany
Tel: +49 (0)3834-864095
Fax: +49 (0)3834-864114
[1]http://biogeo.botanik.uni-greifswald.de

Dr. Tom Melvin
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Phone: +44-1603-593161
Fax: +44-1603-507784

--
Martin Wilmking, Ph.D.
Working Group: Ecosystem Dynamic
Institute for Botany and Landscape Ecology
University Greifswald Grimmer Strasse 88 D - 17487 Greifswald, Germany
Tel: +49 (0)3834-864095
Fax: +49 (0)3834-864114
[2]http://biogeo.botanik.uni-greifswald.de

No comments:

Post a Comment