date: Wed Jun 18 09:39:51 2008 from: Keith Briffa subject: Re: Review of your Holocene submission to: "Nathan Malcomb" Nathan this is a difficult one - because I suspect you may be able to improve the standardisation to some extent but not by generally available approaches - my best suggestion would be that you might simply note the potential lack of lower frequency info and still present the results in a sense - as high-pass interpreted data. It turns out the main referee is citing information (it is not me or anyone here by the way) that is not that generally appreciated by many yet as the "recent bias" effect is in a paper (by Tom and me here) that this referee had access to . The chronologies really need standardising with a "signal-free" approach. HOWEVER, THERE IS CLEARLY NO SIMPLE FIX HERE. It is not impossible that if you submitted this elsewhere you might not meet the same objections - but would that be satisfactory in your own mind anyway? Perhaps you could try a revision and then reconsider? sorry that I can not be more positive. best wishes Keith At 16:27 17/06/2008, Nathan Malcomb wrote: Dear Dr. Briffa, Thank you for sendng the first review of the paper. The reviewer noted several undeniable flaws with our mass balance reconstructions, the most serious of which being the short calibration periods used in modeling. This problem stems from the heavy use of Fritz Schweingruber's 1983 chronologies. While many of the review's other suggestions can be addressed, it would not be possible for us to update these chronologies or omit them entirely. Given these limitations, is this paper salvageable for re-submittall to the Holocene? Can you recommend another journal or letter ? Thank you. Nathan Malcomb On Fri, May 16, 2008 at 7:23 AM, Keith Briffa <[1]k.briffa@uea.ac.uk> wrote: Dear Dr Malcomb ( and Greg) I am really sorry for the delay in the review of this paper. The truth is that it is not my fault though. I received one review some weeks ago , but I have been trying for some time to get the other one. I have sent reminders but having received your latest request for news , via John Matthews , I sent another urgent request which has succeeded only in the reviewer informing me that he can not get the review done and asking me to find another reviewer. I am copying the initial review that I have below - but you will see that it is not favorable . You may care to consider the points and perhaps respond as to your likely course of action . In its present form and on the basis of this review , we would be unable to accept the paper for publication. I can if you wish send it out to another reviewer (perhaps you may even like to suggest one?). However we would be bound to respect the original reviewer's opinion and would require significant reworking of the paper even so. What course of action would you consider appropriate at this time ? We have now moved to an electronic submission system and you may wish to consider resubmitting a revised manuscript through that route. I apologise again that you have had to wait for this response, but I have to stress that it is getting increasingly difficult to find reviewers who are prepared to dedicate the time needed to undertake careful reviews. I look forward to hearing response best wishes Keith Paper by Malcomb / Wiles Tree-ring based mass balance estimates along the Northwestern Cordillera of North America Conclusion: The paper presents a tree-ring based reconstruction of the glacier mass balance evolution in Northwestern North America for the last few centuries. However, the dendrochronological methods used are inadequate for centennial reconstructions. Moreover, the calibration periods are shortened due to optimize the calibration results. This ends up in very short calibration periods. There are no statistical tests for the stability of the glacier tree ring relationships on which the calibration is based for the reconstruction period. Even some important references are not used. The paper should not be published with these major problems. Some details: Line 30: glacier-climate relation: statement that glacier size changes only can display at least multi-decadal fluctuations is too general directly observed length change records of some glaciers even document inter-annual reactions Line 47 and following: even European references on tree-ring based glacier mass-balance reconstructions should be used e.g. Raper et al., who discuss the important point of changing meteorological conditions and their influence on the reconstruction results Line 15: the calibration periods are extremely short shortened to optimize the calibration results. This in combination with multiple predictors selected out of a set of data due to good statistical results leads to high correlations for the calibration periods. However, the authors mentions that this calibration is not stable for recent years. Additionally there is no test of these reconstructions for the past. The authors could at least test the stability of the relationships between the tree-ring chronologies used for the reconstructions for the reconstruction period (e.g. running window correlations). Line 109: It is well known that individual standardisation of tree-ring series does not allow reconstructions for frequency bands greater than the mean segment length of the single series. Additionally this standardization produces even end effects that might be at least partly responsible for the a divergence problem in recent years. Because the study aims on a multi-century long mass balance reconstruction other standardisation methods should be used. The missing long term trend (e.g. in comparison the Northern Hemisphere temperatures as displayed in Fig. 3) of the mass balances reconstructions are probably a direct standardisation artefact Line 116 and following: the paper limits the time period for the calibration of the tree-ring mass-balance relationship by a simple statement on "model instability" in the recent years. It is too simple to say, that tree rings lost their climate sensitivity (high frequency or low frequency band ?) in recent years and therefore to exclude the last approx. 20 years of observation. General: - instead of "instrumental mass balances" the term "glaciological mass balances" should be used, because glacier mass balances are not measured by using an instrument - additionally and to avoid confusions, tree-ring based mass balances data are "reconstructed mass balances" - the paper compares the mass balance reconstructions with the individual and regional glacier history (e.g. fig. 3) therefore the known history of the glaciers used should be shortly mentioned: know LIA glacier maximum, history since this max, distance of retreat - The reconstructed mass balances are not really compared with local and regional glacier history. Some reconstructions show an overall positive mass balance trend for the last c. 200 years is this in accordance with "real" glacier evolution? Figures and tables: - Figure 2 and 3: instead of characters the names of the glaciers itself should be displayed in the figures, figure 3: what kind of data is displayed should be indicated - Table 1: more information on the tree-ring sites and chronologies used is necessary: number of trees in the chronology, mean segment length, inter-correlation of the series, altitude of site, distance of the site to local tree line -- 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/ -- Professor Keith Briffa, Climatic Research Unit University of East Anglia Norwich, NR4 7TJ, U.K. Phone: +44-1603-593909 Fax: +44-1603-507784 [3]http://www.cru.uea.ac.uk/cru/people/briffa/