Wednesday, November 30, 2011


date: Mon, 11 Oct 2004 17:00:52 +0100
from: Keith Briffa <>
subject: [Wg1-ar4-ch06] IPCC last 2000 years data

Friends and authors ( especially Ricardo, Olga, Fortunat, David, Ramesh,
Zhang, Dan, Eystein and Valerie)
Now back from travels (until Wednesday when off to Austria for a few days)
I thought it best to suggest a break down for the writing of the data
section for the last 2000 years of the IPCC palaeoclimate chapter. Please
see the outline produced at the meeting. We have 4 IPCC pages . I will
write a short intro linking to the instrumental data with links to Chapters
3-5. I will coach this in a general introduction to this section that
addresses the points listed in the initial notes ( namely how we use the
various high , and few low, resolution data to construct regional and
large-scale temperature variability , and where possible, gain insight into
hydrologic variability. I will say we use models to get insight into
methodology and to explore regional coverage and seasonality issues and we
use control and forced model runs to look at sensitivity and detection
issues , but also use date to test model variability and sensitivity .
I can first go at the NH (SH) Spaghetti diagram discussion and hopefully
you will pick up the regional aspects of the temperature and precipitation
(moisture) variability .
Rather than me say - I would like you to come back with the major areas you
will cover , but these may best be done in terms of climatologically
meaningful regions - ie relating to the ENSO, NAM, PDO , AAO, monsoon areas
- then we could fill in the remaining regions if significant non overlap in
areas is apparent (Eurasia, non-monsoon china etc) . We do not want a list
of every paper ever written , but a selection of (the better) work that you
feel has regional relevance (and some length presumably). THe other
alternative is just to divide up the world to our own regions and then
discuss the climate indices separately. This would likely be easier to do .
Let me know what you think. Either way , we also should have a specific
discussion of forcings at high resolution , and Fortunat, Valerie could
cover solar and volcanic , perhaps Eystein discussing what evidence there
is for THC change . The knotty issue of THC versus NAO and the link to
model theories/models could go here - or perhaps later in the section ? Davis what say you about this? The same is true of ENSO links to
terrestrial precipitation patterns and temperature?
I don't like the idea of dealing wit quasi periodicities separately , but
rather wit the regional discussions eg North American drought. The
question of LIA , MWP will come up in the large scale average discussion
but you can also address it in the regional discussions , but in a critical
and quantitative way. I would like to see the evidence for extremmes/abrupt
change from the regional syntheses and then see if we have enough to define
and discuss the issue separately. Olga could you pick up on the glacial
variations (perhaps with links to models also?)

So come back to me asap to let me know impressions and regional/variable
focus you all wish to pick up. Ricardo will obviously do North South
linkages as per the PEP1 transect , but what about along PEP2 and 3/ WE may
have to pick this up in the light of the regional data. Can you also let me
know if/who you might be asking to help with writing . Peck , I would still
rather have Mike Mann in , so what is the story here - can I ask him?
Suggestions for summary Figures still welcome - I would like to have a High
lat , mid lat , low lat transect type figure for temperature , possibly
along each PEP transect - with longest instrumental data . A forcing
diagram is also a must - but could combine Holocene and "blow up " last
2000 years.

Best wishes

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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