Saturday, March 17, 2012

2575.txt

date: Thu Jul 5 12:01:58 2001
from: Keith Briffa <k.briffaatXYZxyz.ac.uk>
subject: Re: NGRIP
to: Ian Snowball <Ian.SnowballatXYZxyzl.lu.se>, atte.korholaatXYZxyzsinki.fi, Nalan.Koc@npolar.no, atle.nesje@geol.uib.no

Ian
I am attaching a piece of text and a Figure I put together for something I am doing for the
PAGES synthesis (with Ray Bradley and others) . This piece relates only to the last 1000
years and only for circum N.Atlantic records - the original idea was only to look at
highest resolution records so a lot of stuff was omitted that will go in the HOLIVAR piece.
{incidentally I am pushing for more space in the full paper to include long Holocene
records from Atte and perhaps the speleothem record from Lauritzen - will discuss with Atte
later.
There are a number of dendro records (Norway, Finland, Sweden , Russia ) that go back 100s
to 1000s of years but do not show millennium -timescale variability (even with methods of
processing that should preserve it- Also see the Figure in PAGES Vol.7. No.1 ,March 1999,
Page 6) yet there are tree-line data (Elevational and latitudinal - In Sweden and Russia)
that do show major changes. This aspect needs discussing and I am trying to put together
something for a Holocene paper on this issue - but can air it here. However , my question
is what space do we have and is it best just to concentrate on last 2000 years? Equally ,
how many overheads from each of us will you want.? I really wonder whether we can have a
camera ready copy by Aix - It needs feedback and discussion between us of where to put
emphasis or attempt new syntheses which will require more work.
Incidentally, I would like to use the Sigfus Johnsen data (I presume these are decadal
means?) to replace the North GRIP data I extracted from a Figure (produced by Claus Hammer
I recall) in the attached Figure. Would that be OK?
best wishes Keith
P.S. Legend to Figure is as follows :
Figure 6.20. Selected climate-related records for the last millennium around
the region of the northern North Atlantic. All of the series are plotted as
effective 10-year (thin line) and 50-year (thick line) smoothed and
standardized values (with reference to the common base period 1659-1999).
a. Central England mean annual temperatures (Manley, 1974; updated by the U.K.
Meteorological Office); b. Pseudo annual temperatures for the Benelux countries
(produced from data in van Engelen et al., 2001); c. reconstructed winter (NDJ)
North Atlantic Oscillation indices (Luterbacher et al., 2001); d. warm season
(A-S) N. Swedish temperatures reconstructed from tree-ring data (Briffa et al.,
1992); e. moisture index based on bog flora in western Britain (Barber et al.,
2000); f. Bermuda Rise SST reconstructed from Foraminifera oxygen isotope composition
(Keigwin, 1996); g. an index of the speed of deep current flow to the north west of
Scotland (Bianchi and McCave, 1999); h. foraminiferal abundance in the Cariaco
Basin, off Venezuela, indicative of trade wind intensity and possible changes
in temperature in the North Atlantic (Black et al., 1999); i. oxygen isotope
data from the North Grip site ice core (Hammer, 2000); j. combined series of
ice-core-derived oxygen isotopes from the GISP2 and GRIP sites in central
Greenland (best refs?); k. a composite series of several west Greenland
ice-core oxygen isotope series (Fisher et al., 1994); l. high-resolution
melt-layer data in an ice core from northeast Canada (Fisher ?); m. a
lower-resolution eastern Canadian ice-core melt record.
At 11:18 AM 7/5/01 +0000, Ian Snowball wrote:

Hi All,
Sigfus Johnsen has given me delta 18O data from NGRIP (see JQS, 2001, 4,
299-307).
The N.Greenland records appear to be more sensitive to climate change than
central Greenland (and they admit that they don't know why). In any case,
these data form the best Holocene ice-core record and we are allowed to use
it. I suggest some kind of diagram of selected high-resolution Holocene
records vs the NGRIP data.
I would also like to include a figure from Lena Barnekows "hidden" article
in JOP, 2000, v23, 399-420. Her figure 14 is based on macrofossil AND
pollen records, and shows the development of tree-line changes in the
Abisko area very well. We can discuss this figure in terms of tree-line
response to long periods of uninterrupted "warmth". I never really
understood why she chose to publish this article in JOP! I'll try to choose
one of Atle Nesjes figures and compare with other data sets.
So, ATTE, can you send me your July temp vs cal. BP data from Quat. Res.
(2000) Fig. 4? Basically the smoothed RED line in Fig. 4a!
Keith: do you have any dendro curve that you may wish to comapare?
Cheers,
Ian.

Ian Snowball
Docent (Associate Professor)
Department of Quaternary Geology
Lund University
Tornav�gen 13
S-223 63 Lund
Sweden
Tel: +46 46 222 7889
Fax: +46 46 222 4830
[1]http://www.geol.lu.se/personal/ias/ehome.xtm
Fax: +46 46 222 4830

--
Dr. Keith Briffa, Climatic Research Unit, University of East Anglia,
Norwich, NR4 7TJ, United Kingdom
Phone: +44-1603-593909 Fax: +44-1603-507784

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