Wednesday, March 28, 2012

2944.txt

cc: t.osborn@uea.ac.uk,p.jones@uea.ac.uk
date: Mon, 03 Nov 2003 16:51:31 +0000
from: Keith Briffa <k.briffaatXYZxyz.ac.uk>
subject: follow up as per Mike's comments earlier?
to: mann@virginia.edu,rbradley@geo.umass.edu,mann@virginia.edu, mhughesatXYZxyzr.arizona.edu

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Mike , Ray, Malcolm
We three have been discussing the weeks shenanigans and thought we should
start the wider discussion on the concept and practical aspects of someone
(perhaps us - perhaps not us) doing the "independent" audit of your 98
and/or 99 work. It is clear that the debate as regards the M and M results
will now likely stall , until one or more people undertake this - but it is
unlikely to go away until such time as something is done. The problem ,
however, is what this audit would set out to do.
If it constitutes taking the exact same data and exact implementation of
your method - there seems little value in doing it - the result will be
identical to your result(s). The question then , revolves around a fuller
experiment in the use of various selection criteria for retaining subsets
of the predictors , and presumably working towards gaining some better
impression of the stability of the results , and the sensitivity to the
inclusion of particular predictors. We could perhaps also compare results
with those achieved using other methods (such as our Orthogonal Spatial
Regression)? We would not be attempting to do any new reconstructions.
The question then , stimulated again by Mike's message , and the message
from the Editor of E and E, is whether we should consider going ahead here,
with some such work?
We are already motivated to look at the role of the tree-ring data (in
collaboration with Malcolm and Ed hopefully, looking at stuff like
standardisation issues, the western U.S. recent trend correction etc.) ,
but we feel some discussion among all of us would help to clarify opinions
and prospects for a wider look at the robustness of the Mann98/99 result.
We have no particular axe to grind , but it is almost certain that there
will be some pressure for some such work, and we suspect that DEFRA here
will be quizzed by various bodies for their opinion on this. If so, why not
us rather than others ?
It may be that anything we do here would not be seen as "independent" by
the skeptics anyway ( and we would not consider doing it without some
appropriate level of interaction with you lot) - but in the end , what
counts, is what is published in the peer-review literature.It was important
to get your statement out , but it needs to be followed up now by one or
more studies by other groups. We could go with the candidate predictor set
you used and do a Monte Carlo approach to selection over different periods
, or add in other predictors or ....what? What do you think? We might need
to go for a very small amount of money from DEFRA ( to pay Harry or someone
just to manipulate palaeo data , and then after implementing the method(s)
and deciding on the scheme, run the numerous experiments and synthesize
results), or we may be able to do it by diverting his time from some other
stuff anyway.
To get the discussion going , we wish to ask your opinion(s) on the
concept, level of interaction between us and you guys ( in planning , or
also implementation , and synthesis, writing up?). What about this issue of
our perceived independence - do we give a damn?
Keith, Tim, Phil

--
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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