date: Fri, 03 Feb 2006 17:04:39 +0000
from: Keith Briffa
subject: Fwd: Re: Fwd: new fig
to: Tim Osborn
>Date: Fri, 3 Feb 2006 09:49:06 -0700
>To: Keith Briffa
>From: Jonathan Overpeck
>Subject: Re: Fwd: new fig
>Cc: Eystein Jansen , t.osborn@uea.ac.uk
>X-Virus-Scanned: amavisd-new at email.arizona.edu
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>
>Keith and Tim - I do like what you did, and I
>could figure it out. That said, Eystein's
>response highlights the importance of my
>suggestion to start early on the caption so we
>can get it perfect. The presentation is not
>intuitive, so we have to educate. BUT, there is
>no doubt in my mind that this is more appealing than the FOD approach.
>
>thanks, peck
>
>>Eystein
>>the shading represents overlaps of the
>>uncertainty estimate envelopes surrounding each
>>of the 10 reconstructions . If one
>>reconstruction curve is envisaged , it has 1
>>and 2 standard error bounds above and below
>>each smoothed value. We are trying to represent
>>the most likely temperature based on all
>>reconstructions. SO if their inner (most likely
>>) 1 standard error bands all overlap , we want
>>to show a high score . If only the outer
>>uncertainty bands overlap between a small
>>number of reconstructions, we need to say it is
>>unlikely that this is the likely temperature -
>>so a small score. Hence we allocate 2 points to
>>all areas within the 1 standard error range of
>>each reconstruction, and 1 point for the area
>>between 1 and 2 standard errors. Then we
>>overlap all reconstructions and count the total
>>score. They go from maximum (20) WHERE THE PLUS
>>AND MINUS 1 STANDARD ERROR Envelopes (i.e. a
>>66 percent chance that the "real" value lies in
>>this band) OVERLAP FOR ALL RECONSTRUCTIONS
>>(each of the possible 10 gets a score of 2 in
>>this area) to 0 , where no reconstruction uncertainty envelopes overlap.
>>If only the 1 standard error envelopes overlap
>>for each of 2 reconstructions , the score is 2,
>>and if the inner uncertainty band overlaps with
>>the outer uncertainty band of only 1 other
>>reconstruction , the score is 3 and so on.
>>Hence the high scores show where most
>>reconstructions most likely estimate ranges
>>overlap. This gives prominence to the middle
>>estimate of the most abundant reconstructions,
>>and less emphasis on those estimates based on
>>only a few or even 1 reconstruction. Hence the
>>scores are low where there are few
>>reconstructions, and low where the confidence
>>in the reconstructions is low. Now you can see
>>that the most likely estimates for the MWP are
>>lower than those for the recent period - this
>>is better than showing the total uncertainty
>>range which is controlled by outliers - such as Moberg's curve.
>>
>>
>>
>> At 14:40 03/02/2006, you wrote:
>>>Hi Keith, could you just explain the values
>>>reflecting the colour shading n the lower panel?
>>>Eystein
>>>
>>>>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
>>>>Keith
>>>>
>>>>>X-Mailer: QUALCOMM Windows Eudora Version 7.0.0.16
>>>>>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
>>>>>
>>>>>e-mail: t.osborn@uea.ac.uk
>>>>>phone: +44 1603 592089
>>>>>fax: +44 1603 507784
>>>>>web: http://www.cru.uea.ac.uk/~timo/
>>>>>sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm
>>>>
>>>>--
>>>>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/
>>>>
>>>>Attachment converted: Nebbiolo:ipcc_nhrecon_new1.pdf (PDF /«IC») (00A6614D)
>>>
>>>
>>>--
>>>______________________________________________________________
>>>Eystein Jansen
>>>Professor/Director
>>>Bjerknes Centre for Climate Research and
>>>Dep. of Earth Science, Univ. of Bergen
>>>Allégaten 55
>>>N-5007 Bergen
>>>NORWAY
>>>e-mail: eystein.jansen@geo.uib.no
>>>Phone: +47-55-583491 - Home: +47-55-910661
>>>Fax: +47-55-584330
>>
>>--
>>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/
>
>
>--
>Jonathan T. Overpeck
>Director, Institute for the Study of Planet Earth
>Professor, Department of Geosciences
>Professor, Department of Atmospheric Sciences
>
>Mail and Fedex Address:
>
>Institute for the Study of Planet Earth
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>direct tel: +1 520 622-9065
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>http://www.ispe.arizona.edu/
--
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/