Friday, May 18, 2012

4421.txt

cc: "'Stephen T. Gray'" <sgrayatXYZxyztana.edu>
date: Fri, 17 Oct 2003 13:57:08 -0600
from: "Graumlich, Lisa" <lisaatXYZxyztana.edu>
subject: RE: help with an idea?
to: 'Keith Briffa' <k.briffaatXYZxyz.ac.uk>, "'cbaisan@ltrr.arizona.edu'" <cbaisanatXYZxyzr.arizona.edu>, "'drdendro@ldeo.columbia.edu'" <drdendroatXYZxyzo.columbia.edu>

Dear Keith, Chris, and Ed,

Keith, thanks for getting this conversation going. I would be happy to
contribute the CA data to this effort.

I should also mention that my post-doc, Steve Gray, and I have been
exploring some similar ideas and are very interested in contributing to a
larger project. Attached is our AGU abstract as well as our reconstruction
of the AMO. In particular, Figure A shows North Atlantic (0-70N) SST
anomalies extracted from the Kaplan et al. 1998 reanalysis data (in SD
units). The bottom graph (Fig B) is our tree-ring based reconstruction of
SSTA spanning 1567-1990 AD. The black lines represent annual values and the
red line shows a 10-yr spline. The data for the reconstruction come from
Eastern North America, Europe, Scandinavia and the Middle East. We are
combining theses results with our new tree ring data from the inner Mountain
West to explore PDO-AMO interactions.

It strikes me that we might want to have a conference call, or at least some
spirited email, to discuss some ideas for collaboration.

With best wishes, Lisa





Lisa J. Graumlich
Executive Director, Big Sky Institute
406/994-5320

-----Original Message-----
From: Keith Briffa [mailto:k.briffa@uea.ac.uk]
Sent: Friday, October 17, 2003 8:24 AM
To: lisa@montana.edu; cbaisan@ltrr.arizona.edu; drdendroatXYZxyzo.columbia.edu
Subject: help with an idea?

Hi Lisa and Chris and Ed

The first point of this message is to ask for access to the raw data for
the Boreal and Camp Hill Foxtail
pine chronologies (Lisa) that I believe you and/or your students produced
and similar data that you may have (Chris). for the area inland of the
Santa Barbara Basin , California. I am also trying to stimulate your
interest and hopefully start a joint collaboration (Lisa , Chris and Ed).
Please allow me to explain .
I was reading some papers on the putative link between North Atlantic
temperatures (oxygen isotope record from Greenland) and climate
(bio-turbation index) in the Santa Barbara basin , on the 1000-year time
scale (papers by Boyle and Leuschner et al. in the PAGES QSR Volume
published in 2000).
It got me to thinking whether a robust regional temperature chronology for
North west Scandinavia might show any associations with any climate factors
as represented in either high or low elevation tree-ring chronologies in
Western California , at higher temporal resolution (perhaps decades to
century) - and hence whether there is any evidence for a thermohaline link
(or other more direct dynamic atmospheric connection) operating on
various time scales. Of course there are problems with what specific
climate response one would investigate (in terms of season and variable).
However, as a first look I compared our Tornetrask temperature
reconstruction (JJA in Northern Sweden) with a (very) few series I had for
the west US - among which were the chronologies mentioned above from AD 800
that Jan Esper and Ed produced for their Science paper, using data
supplied by Lisa I believe .
Now I don't actually like the general way they applied the RCS ( - using
a very large scale standardisation curve based on disparate data from a
very wide expanse of sites across the Northern Hemisphere - but as Ed might
say " it seems to work "). However, the association between the Tornetrask
series and the curves for Boreal/ Upper Wright have stimulated me to try
to look deeper and solicit your interest and help. In my opinion, for the
600-year period between AD 1100 and 1700 the similarity in the 5
circa 120-year cycles that make up these series certainly warrant serious
further study. The similarity is not apparent before this but the two
California series themselves show little agreement in the earlier 300 years
of data that I have seen, implying that the common signal at the regional
level may not be well represented in either anyway. This could be a
standardisation issue though. By producing more robust mean series and
especially by extending the series back before the post Christian era we
could significantly extend the power of the comparison. I would like to
establish well replicated series (using more-local RCS curves based applied
to more, and longer, data) for both the Tornetrask (and possibly Northern
Finnish) region and the combined set from Upper Wright and Boreal and any
other nearby Foxtail data ( from the region of the 118 degrees west 36
degrees north) . We have earlier (than circa AD 800 ) data for Tornetrask
and Finland , showing good inter region coherence .
If we can establish stronger evidence of a North Atlantic/Eastern Pacific
link (at different time scales perhaps) we can look at other high
resolution records to establish the nature of the likely forcing and the
possible climate dynamic mechanisms.
What do you think? Can I play with your data to this end ? Whatever you
think , I would appreciate it if you would treat this as confidential and
any thoughts on the idea , or pointers to relevant data sets are still
welcome.
All the very best
Keith

--
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.

Phone: +44-1603-593909
Fax: +44-1603-507784

http://www.cru.uea.ac.uk/cru/people/briffa/


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