Saturday, April 14, 2012


date: Fri Feb 3 14:31:09 2006
from: Keith Briffa <>
subject: Fwd: new fig
to: Jonathan Overpeck <>,

Peck and Eystein
we are having trouble to express the real message of the reconstructions - being
scientifically sound in representing uncertainty , while still getting the crux of the
information across clearly. It is not right to ignore uncertainty, but expressing this
merely in an arbitrary way (and as a total range as before) allows the uncertainty to swamp
the magnitude of the changes through time . We have settled on this version (attached) of
the Figure which we hoe you will agree gets the message over but with the rigor required
for such an important document.
We have added a box to show the "probability surface" for the most likely estimate of past
temperatures based on all published data. By overlapping all reconstructions and giving a
score of 2 to all areas within the 1 standard error range of the estimates for each
reconstruction , and a score of 1 for the area between 1 and 2 standard errors, you build
up a composite picture of the most likely or "concensus" path that temperatures took over
the last 1200 years (note - now with a linear time axis). This still shows the outlier
ranges , preserving all the information, but you see the central most likely area well ,
and the comparison of past and recent temperature levels is not as influenced by the
outlier estimates. What do you think? We have experimented with different versions of the
shading and this one shows up quite well - but we may have to use some all grey version as
the background to the overlay of the model results.
We have also experimented with changing the normalisation base for the model/reconstruction
Figure , but using the same short modern period as for the first Figure is not satisfactory
- more on this later. We have added in Oerlemans curve as many insisted - but we only have
the GLOBAL curve - can you get the separate North and Southern Hemisphere curves (with
uncertainty) . I do not see that the new model runs from Germany/Switzerland will fit
easily in the existing Figure and need to be separate! I am really struggling with the text
also - really need more time!!!! More later

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Date: Fri, 03 Feb 2006 10:42:15 +0000
To: Keith Briffa <>
From: Tim Osborn <>
Subject: new fig
Dr Timothy J Osborn
Climatic Research Unit
School of Environmental Sciences, University of East Anglia
Norwich NR4 7TJ, UK
phone: +44 1603 592089
fax: +44 1603 507784
web: [1]
sunclock: [2]

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

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

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