date: Mon Oct 7 12:49:12 2002 from: Keith Briffa subject: Re: NER/T/S/2002/00440 to: "Rapid Rapid" 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]/