date: Tue, 22 Sep 2009 13:20:56 -0400 from: Jason Smerdon subject: Re: invitation to be a co-author to: t.osborn@uea.ac.uk Hi Tim, I have had a chance to go over the paper and include some editorial comments in track changes mode of the attached document. They should all be self explanatory. Below is a list of some specific comments for further consideration. I of course defer to your judgement on whether or not you think the suggestions are worth addressing. Thanks again for including me on this and let me know if you need any further assistance (or clarifications on what I write below). Many greetings from Spain and Fidel, Jason ------------------------ Some Specifics 1. In Section 2 I have described the uncertainty calculations for the boreholes. The estimates I sent you were +/- 1 SE of the mean trends, but I seem to remember you mentioning a 2 SE estimate would be more in keeping with the 95% CI that are typically presented for other recons. I think we had some back and forth with Henry on this, but please adjust the text to what you have done for the plot, i.e. used either 1 or 2 SE. 2. I have included references where appropriate in the text, but the instrumental discussion needs to be clarified a bit. The Australian data were a collection of high-quality data that Henry acquired while down under. We cited them in Pollack et al. 2006 with two refs: Torok SJ, Nicholls N. (1996) A historical annual temperature dataset for Australia. Australian Meteorological Magazine, 45, 251260. Della-Marta PM, Collins DA, Braganza K. (2004) Updating Australias high-quality annual temperature dataset. Australian Meteorological Magazine, 53, 7593. You may want to simply cite Pollack et al. 2006 for these data or the above two refs. 3. The African data were actually from you when we were preparing the IPCC figures. I assume that they were derived from some version of gridded CRU data for southern Africa, but I don't think you sent specifics beyond that. Perhaps you have it in your records? 4. In the first paragraph of Section 3 you compare the SH and NH forcing series. Is it worth plotting the difference between these two series as an inset or additional panel? It might be a helpful complement to the descriptions you provide in writing, but I don't feel too strongly one way or the other. 5. Section 3, end of 4th paragraph. You mention the difference between Ricardo's recon using his station data calibration and the new CRUTEM3v record. You might qualify this a bit more. If the tree recons were calibrated on this new instrumental data they would of course match the record better. It is also worth pointing out how the station data estimate matched the old CRUTEM2v grid-box estimate, i.e. are the differences you report due to updates in CRUTEM3v or between the station data and the gridded estimates that would also have existed in the CRUTEM2v data? 6. Is it correct that the model uncertainties were estimated from the variability of the control run or has something else been done? If the latter, is it possible to provide uncertainty estimates for the NAT500 simulation? I think this would weaken the case somewhat (namely the degree to which the NAT500 and ALL500 sims can be said to be different), but it would perhaps be the most honest way of presenting the comparisons. 7. Section 3, middle of 6th paragraph. Sentence beginning "There are some periods..." I am not entirely clear what you are saying here. Are you saying that the proxy recons do not include full uncertainty estimates? This could be clarified. 8. I am a little concerned about the borehole referencing and the new CRUTEM3v series. You discuss in the last paragraph of Section 3 that the borehole recon sits predominantly above the simulation. But if the new instrumental series is significantly different from what we originally used, the borehole recon would need to be rereferenced to the new series. To my eye it looks like the borehole recon is sitting a bit above the trend in the instrumental time series and a rereferencing would bring the recon down to where it would agree with the simulation more. If you send me the raw instrumental time series and the borehole recons that you plotted, I could check this... 9. In Table 1 you report correlations between the borehole, model and instrumental series. Is this really meaningful, given that the borehole series are just interpolated trends? Would it make more sense just to compare the estimated borehole trends and those from the instrumental and model data during their period of overlap or say just for the 20th century? 10. In the Intro you mention wether we should include additional refs on uncertainty in recons. You could certainly expand this list with more of the usual suspects (Esper and Burger refs would certainly work). I also like to use some of Mike Evans' work for these kinds of things. This is a good paper that includes a lot of uncertainty discussion: [1]http://www.agu.org/pubs/crossref/2002/2000PA000590.shtml Figure 10 is particularly relevant for discussions on how uncertainties are timescale dependent. I also like Mike's process-model paper as support for the need to understand the multivariate and non-linear impacts in tree-ring responses (and associated uncertainties): [2]http://www.agu.org/pubs/crossref/2006/2006JG000166.shtml Attachment Converted: "c:\eudora\attach\paleodata_model_sh_ver09_jes.doc" On Sep 14, 2009, at 5:35 PM, Tim Osborn wrote: Hi Jason, two weeks or so would be fine... my hint at a relatively quick turnaround was to avoid suggestions of major extra work (e.g. "why don't you include results from X other GCMs too?"). I'd like to submit by mid October. Not sure where yet; perhaps have a think about journal when you read it in detail? Unfortunately Keith has been off sick for 3 months, having had to have one of his kidneys removed. He seems to be on the mend, will probably be back at work in October. Other than that, I think we're all ok in CRU. Please say "hi" to Fidel from me. Tim On Mon, September 14, 2009 4:17 pm, Jason Smerdon wrote: Hi Tim, Wow. Thanks for including me on this. I would be happy to be on the paper (I can say that after only a quick scan!). I am also happy to get you comments ASAP. My only problem right now is that I am leaving for Spain on Thursday to spend much of the fall with Fidel G-R in Madrid. I therefore expect that this week and next will be quite busy. It is possible I can have it done earlier (I will have lots of time on the plane), but would two weeks be slow for a turn around time? Please feel free to be blunt if you had an earlier date in mind...I don't want to slow you up. Bottom line: thanks for including me on this and I will work to get you comments as fast as possible. It was nice to hear from you and I hope all is well with you and everyone else at CRU. Please send my regards to Keith and the others. All the best, Jason P.S. Did you have a target journal in mind? On Sep 14, 2009, at 10:43 AM, Tim Osborn wrote: Hi Jason, I've now finished drafting a palaeodata-model comparison paper using the HadCM3 ALL250/NAT500 runs, with a focus on Southern Hemisphere records. I've used the SH reconstructions that we showed in the Palaeoclimate chapter of IPCC AR4. These included borehole recons from Africa and Australia. It would be great if you would agree to being a co-author on the paper, since it makes extensive use of SH borehole recons, plus I'd value your comments on the manuscript as a whole and with some specific sections about the borehole records. I've taken the liberty of including your name on the complete draft that is attached. Of course if you'd prefer not to be an author, that is fine -- just let me know and I'll remove your name in that case. But hopefully you'll agree :-) If so, please send comments, edits etc. to me. It's fairly short. I haven't had any papers as first author since 2007(!) so I'm under some pressure to submit it soon... hopefully you won't suggest any major alterations! Best wishes and hope all's well with you, TimDr Timothy J Osborn, Academic Fellow Climatic Research Unit School of Environmental Sciences University of East Anglia Norwich NR4 7TJ, UK e-mail: [3]t.osborn@uea.ac.uk phone: +44 1603 592089 fax: +44 1603 507784 web: [4]http://www.cru.uea.ac.uk/~timo/ sunclock: [5]http://www.cru.uea.ac.uk/~timo/sunclock.htm -------------------------------------------------------------------------------------- Jason E. Smerdon Storke-Doherty Lecturer Lamont-Doherty Earth Observatory and Department of Earth and Environmental Sciences Columbia University 61 Route 9W, P.O. Box 1000, Palisades, NY 10964 Phone: (845) 365-8493 Email: [6]jsmerdon@ldeo.columbia.edu Web: [7]http://www.ldeo.columbia.edu/~jsmerdon Skype: jason_ldeo -------------------------------------------------------------------------------------- -- Dr. Tim Osborn RCUK Academic Fellow Climatic Research Unit School of Environmental Sciences University of East Anglia Norwich NR4 7TJ, UK [8]www.cru.uea.ac.uk/~timo/