date: Thu Jul  5 12:01:58 2001
from: Keith Briffa <k.briffa@uea.ac.uk>
subject: Re: NGRIP
to: Ian Snowball <Ian.Snowball@geol.lu.se>, atte.korhola@helsinki.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
     Tornavgen 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

