Saturday, April 28, 2012

3620.txt

date: Tue Jun 6 14:30:55 2006
from: Tim Osborn <t.osbornatXYZxyz.ac.uk>
subject: Re: HOLIVAR poster session 3
to: "Sonechkin D.M." <dsonechatXYZxyzom.ru>

Thanks!
Tim
At 11:15 31/05/2006, you wrote:

Dear Tim,
I shall show a new technique of tree-ring-based reconstruction with
an illustration on the known Tornetrask tree-ring set
(this research is in collaboration with my colleague Nina Datsenko
from HydroMeteoCenter of Russia, and with H.grudd and a. Moberg from the Stockholm
University).
The essence consists of the use a new index dR(t)*R(t)-Mean(dR(100)*R(100))
where dR(t) - ring width of the year t, R(t) - the inner radius of this ring,
Mean(dR(100)*R(100)) - mean value of the product for 100-year old trees
calculated for consequent time intervals of 200 or 500 years in their length.
This quantity is a characteristic of general environmental conditions during respective
time intervals,
and so it admits to represent lower-frequency responses of trees to varying climatic and
environmental conditions.
Note, our index is similar to the know basal area increment index, but it is robust to
deviations of the stem geometry
from ideal circle.
Our index is age-insensitive for mature trees (.100 year old).
The first of attached reconstruction (they cover more than the latest 2000 y)
is created with use all mature trees from the Tornetrsk set.
One can see that the MWP and the Roman warm epoch were warmer then the current climate.
But one can see some delta-like peaks in the reconstruction by the reasn of poor
sampling for respective time moments.
Therefore, the second and third reconstruction are created with use the only cases when
more than 3 or 5 tree-rings
exist for a year. All peaks are absent in the third reconstruction, but some gaps exist.
Green line shown in the third reconstruction represent an estimation of temperature
variations BP
published by a Swedish paleoclimatologist Moerner (1976). He used dO18 in sediments of
the Tingstedetrask lake
(Gotland).
One can see the third reconstruction cartch rather well the manycentennial temperature
variations indeed.
Dmitry Sonechkin
Tim Osborn wrote:

Hi everyone,
sorry for the mass posting, but as there are so many of you I couldn't send out
individual requests.
I have the honor of introducing the poster session for theme 3 (Climate variability in
the last 2000 years) of the HOLIVAR conference, for which you are all listed as
presenting posters.
In my 15 minute slot I will try to mention as many of your posters as possible, or at
least groupings of those in common themes.
It would be nice if I could show a figure from many of the posters to induce the
audience's curiosity so that they go and find out more from you/your poster. Obviously
I wouldn't have time to explain anything in detail.
If you would be willing, then please send me one figure from your poster (JPEG, GIF,
PNG, PDF etc. including caption) and I will try to include it.
If you have not yet made your poster, then it does not matter too much if you send a
figure which is not identical to your final choice for your poster... as I said it is
just to whet the audience's appetite.
Best regards
Tim
Dr Timothy J Osborn, Academic Fellow
Climatic Research Unit
School of Environmental Sciences, University of East Anglia
Norwich NR4 7TJ, UK
e-mail: t.osbornatXYZxyz.ac.uk
phone: +44 1603 592089
fax: +44 1603 507784
web: [1]http://www.cru.uea.ac.uk/~timo/
sunclock: [2]http://www.cru.uea.ac.uk/~timo/sunclock.htm

No comments:

Post a Comment