cc: "Raymond S. Bradley" <rbradley@geo.umass.edu>, mhughes@ltrr.arizona.edu, k.briffa@uea.ac.uk, tom@ocean.tamu.edu, p.jones@uea.ac.uk, td@gfdl.noaa.gov, hpollack@geo.lsa.umich.edu
date: Fri, 2 Mar 2001 10:53:01 -0600
from: tom crowley <tom@ocean.tamu.edu>
subject: Re: Science letter
to: "Michael E. Mann" <mann@multiproxy.evsc.virginia.edu>

Dear All,

A few more comments re Mikes note - Mike and I thought that if we cannot
make a case to our colleagues, why muddy the waters further (as either
Keith, Malcolm, or Ray said)?

That said, I don't think this has been wasted time.  I still think a
thoughtful short paper on the subject of Holocene climate change wold be
useful, this time stating it from OUR perspective (i.e., not focusing
exculsively on Broeckers message).  By broadening this it may be more
interesting; we could also include a couple of figures and maybe add some
input from Tom Delworth and Henry Pollack.  I would be willing to take a
crack at this, and if anyone wants to CONDITIONALLY sign on, I would be
more than happy to include you.

I probably would not begin this until late April, after our trip to Germany
and the meeting in Virginia.

Tom

ps  fyi I  counted the average spacing between the warm and cold
oscillations in the iron oscillations illustrated by Broecker.  Regardless
of whether warm or cold are used, the mean spacing is indeed 1.5 k,
although the s.d. is 0.4k  HOWEVER, the mean spacing between the four main
warm phases illustrated by Broecker on the same figure is, believe it or
not, 2.15!  much closer to the solar peak.  This calls to mind the
interesting (and clever) Wigley and Raper paper  in Proc. Roy. Soc. (1990)
indicating that, given the uncertainties in chronology, solar forcing plays
a role i n Holocenn climate change.  It therefore seems that the conveyor
is indeed oscillating but the time scale of the larger scale CLIMATE shifts
may be more regulated by solar, with volcanism adding some stochastic
contribution.  Something like this is worth adding to the proposed Eos
piece.

Tom



Thomas J.  Crowley
Dept. of Oceanography
Texas A&M University
College Station, TX  77843-3146
979-845-0795
979-847-8879 (fax)
979-845-6331 (alternate fax)


