Monday, June 18, 2012

5322.txt

date: Mon Oct 7 12:49:12 2002
from: Keith Briffa <k.briffaatXYZxyz.ac.uk>
subject: Re: NER/T/S/2002/00440
to: "Rapid Rapid" <RAPIDatXYZxyz.nerc.ac.uk>

Dear Lauren
thanks for these comments . Clearly they are extremely positive but it is
worth responding to some of the specific points where some clarification or comment is
relevant . So here goes , in order...
REFEREE C:
1. There is possible overlap with other researchers such as Ed Cook,and
Stahle. But if the stated collaboration with these and other colleagues
who produce the primary data is firm, this may not be a problem.
There is no conflict in the overlap with other researchers. On the contrary, we emphasize
the fact that these researchers (and others named) have agreed to collaborate actively in
the provision of data and in their interpretaion.
2. The last 1000 years are important. But several paleo records show the
period ~1000-1500 years ago encompasses the very warm earliest part of the
Medieval Warm period. This period is critical in assessing 20th century
warming but prior widely cited studies (Mann et al, Crowley) are limited to
the last 1000 years yet form the basis for statements about the causes of
relative warmth in the 20th century. Effort should be made to include even
the few proxy record going back 1500-2000 years before present.
We agree entirely with this referee that the period just prior to the last 1000 years has
relevance to the issue of climate change detection. Yes, we will make efforts to collect
and amalgamate data prior to AD 1000, but this will not be a priority in the final analysis
because the synergy in the work we propose lies in analyzing the overlap between empirical
data and model-derived (principally GCM) data and this is clearly limited to the more
recent period by the availability of appropriate simulations. We do note, however, the
potential to use the earlier data in combination with simpler model (e.g. EBM ) output and
we further note that a volcanic forcing series has been recently extended (Crowley,
personal communication) and could be used to force the simpler models.
3. The most recent proxy records are nicely cited but given the
investigation is seeking to examine links between NAO variability to
deep-water processes (convection etc), it is unfortunate there are few
marine paleo-records cited. Some exist or are about to be published on the
ocean and NAO and should be sought out, EVEN IF TEMPORAL RESOLUTION DOES
NOT MATCH THAT OF TREE RINGS.
We would accept the advice of the referee here. If the project is funded we commit to
seeking advice from palaeo-ocean specialists about which series to use and how to
quantitatively interpret them.
4. The use of model output for "synthetic" proxy records worries me. More
strategically placed high resolution proxy record, including more in
oceans, are needed and let the models do their own thing.
One of the key elements of our proposed project is to quantify the (potential) utility of
various sets of proxy records - with differing individual "reliability" and geographic and
seasonal coverage. For this element to be comprehensive, we wish to explore beyond the
constraints of available records - thus allowing us to anticipate the benefit obtained from
possible future enhancements of the climate proxy data base. Generating "synthetic" records
from model output will allow us to do this - and even perhaps identify which "strategically
placed high resolution" records offer most benefit for the various problems we will
address. The referee should be reassured, however, that we will not use the model-derived
synthetic records to tell us the past climate history - for that we will use real proxy
records (including suitable oceanic ones).
REFEREE D:
Of course, there are limitations to the data * especially in reconstruction of external
forcings *
We thank this referee for their positive comments. Our only response is to agree that the
data uncertainty (related to climate forcing histories and palaeoclimate interpretation)
should be explicit in the consideration of covariance between empirical and model-based
time series and fields.
Thank you for the opportunity to respond to these and the earlier comments forwarded.
Best wishes
Keith
At 11:25 AM 10/4/02 +0100, you wrote:

Dear Professor Briffa
Please find below, further referee comments on your research grant proposal.
Regards
Lauren
REFEREE C:
This is an excellent, ambitious proposal to conduct research extremely
important to understanding climate variability and its causes in the North
Atlantic region. Investigators are the best, budget is reasonable, and the
integrated nature of the work (atmosphere/ocean, proxy data modeling etc)
is sorely needed.
My only possible concerns are:
1. There is possible overlap with other researchers such as Ed Cook,and
Stahle. But if the stated collaboration with these and other colleagues
who produce the primary data is firm, this may not be a problem.
2. The last 1000 years are important. But several paleo records show the
period ~1000-1500 years ago encompasses the very warm earliest part of the
Medieval Warm period. This period is critical in assessing 20th century
warming but prior widely cited studies (Mann et al, Crowley) are limited to
the last 1000 years yet form the basis for statements about the causes of
relative warmth in the 20th century. Effort should be made to include even
the few proxy record going back 1500-2000 years before present.
3. The most recent proxy records are nicely cited but given the
investigation is seeking to examine links between NAO variability to
deep-water processes (convection etc), it is unfortunate there are few
marine paleo-records cited. Some exist or are about to be published on the
ocean and NAO and should be sought out, EVEN IF TEMPORAL RESOLUTION DOES
NOT MATCH THAT OF TREE RINGS.
4. The use of model output for "synthetic" proxy records worries me. More
strategically placed high resolution proxy record, including more in
oceans, are needed and let the models do their own thing.
REFEREE D:
The proposal outlines an interesting strategy to use models and palaeoclimatic data in a
synergistic way, to evaluate the role of Atlantic variability in past climate changes
affecting Europe. The authors have articulated the main issues that need to be
addressed, and are clearly aware of the data limitations. Bringing together the talents
of Briffa, Jones in empirical data analysis, with Osborn & Tett in theory and modelling
should produce first rate research results.
Weaknesses:
I see no fundamental problems with their approach. Of course, there are limitations to
the data * especially in reconstruction of external forcings * but the authors are
undoubtedly aware of these issues and will no doubt proceed with caution, as
appropriate.
Rapid Climate Change Research Grants Team
Operations Group
Science Programmes Directorate
NERC
Polaris House
Swindon
SN2 1EU
Tel: 01793 411663
Fax: 01793 411655
[1]http://www.nerc.ac.uk/funding

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

Phone: +44-1603-593909
Fax: +44-1603-507784
[2]http://www.cru.uea.ac.uk/cru/people/briffa[3]/

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