cc: Nathan Gillett , Gabi Hegerl , Peter Stott , Toru Nozawa , Alexey Karpechko , Michael Wehner date: Thu Dec 4 14:29:16 2008 from: Phil Jones subject: Re: Fwd: draft “Communication Arising” regarding your recent to: Dáithí Stone Daithi, No myth - it's true and applies to ERA-40 as well. They do have SSTs changing - so they get a bit of the anthro signal that way. There is a Nature comment (Trenberth) on Kalnay and Cai (2003) referred to in Ch 3 of AR4. Calculating the PDO and AMO from SST means you'll get some upward trend as well. The more I think about this comment - the poorer it gets. Cheers Phil At 14:03 04/12/2008, Dáithí Stone wrote: I seem to remember something about the NCEP reanalysis having constant GHG concentrations, but maybe this is just an urban myth? DA On Thu, 4 Dec 2008, Phil Jones wrote: Nathan, A few thoughts. First - most odd that they go on about the Arctic. The warming here is much clearer and the sea ice is disappearing in summer! I can't see their comment getting past reviewers. All of the Arctic and Antarctic stations are manned - at least at the moment. Even though they are manned, the equipment might be automatic, in that readings can be made without going out into the cold! You can't use Reanalyses in the Arctic and especially the Antarctic as they are way off from the observations (Simmons et al., 2004), especially before the satellite era in 1979. The reason they are way off from the obs is that before the satellite era there aren't enough data to overcome model biases. In the Antarctic (fig 6 in Simmons et al) most of the obs get rejected as they are so far away from the model's wrong first guess. You could suggest that they work out (from the Reanalysis - it doesn't matter that it's wrong) how representative the limited Antarctic temperature stations are of the continental average - at the 5 year scale. They will be surprised by the result. A limited number of stations works quite well at this timescale. Suggest they read this paper (Jones et al. 1997) on this. They are confused by daily timescales and the 5-year averages we are looking at. The comparison to Italy is ridiculous. At the 5-year timescale, probably just one or two Italian sites would be all that was needed. The issue here is how many spatial degrees of freedom there is - and this depends on timescale. You have pointed out that their regressions with PDO and AMO are not very clever. They are going to be losing temporal degrees of freedom with their lagged regressors. I bet they are not reducing degrees of freedom because of autocorrelation either. It is quite easy to take any temperature series and show that it can be related to circulation indices. Just because the circulation explains more variability than the climate models doesn't mean that anthropogenic climate change isn't happening. What is causing the circulation to change! Maybe you could add a few references where you've shown D&A for the NAM and the SAM. Anyone tried the AMO or the PDO. Cheers Phil PS Your grant has just paid the page charges from Nature Geosciences! Jones, P.D., Osborn, T.J. and Briffa, K.R., 1997: Estimating sampling errors in large-scale temperature averages. J. Climate 10, 2548-2568. Simmons, A.J., P.D. Jones, V. da Costa Bechtold, A.C.M. Beljaars, P.W. Kĺllberg, S. Saarinen, S.M. Uppala, P. Viterbo and N. Wedi, 2004: Comparison of trends and low-frequency variability in CRU, ERA-40 and NCEP/NCAR analyses of surface air temperature. J. Geophys. Res., 109, D24115, doi:10.1029/2004JD006306. At 21:42 03/12/2008, Nathan Gillett wrote: Hi all, I was sent the attached draft paper, which the authors say they are planning to submit in response to our Nature Geoscience paper, inviting our comments. I've drafted a response - see attached. At this stage, this probably isn't worth spending a huge amount of time on, but let me know if you have further comments. Phil - am I correct in writing that the station data used in CRUTEM3 comes only from manned stations? Cheers, Nathan ---------- Forwarded message ---------- From: Luigi Mariani Date: 2008/12/1 Subject: draft "Communication Arising" regarding your recent Nature Geoscience paper ? please comment To: n.gillett@uea.ac.uk Cc: Maurizio Morabito , Parisi Simone , Gabriele Cola , Paolo Mezzasalma , Teodoro Georgiadis < t.georgiadis@ibimet.cnr.it> Dear Dr. Gillett, We are a group of climate scientists mostly based in Italy. We have read with interest your recent article in Nature Geoscience "Attribution of polar warming to human influence" but have some doubts regarding your conclusions. We have prepared a draft "Communication Arising" for that same publication (enclosed). Before we submit our contribution to Nature Geoscience, we would very much appreciate your comments about our points, with the aim of resolving disputes whenever possible and remove points where we all agree. We are also sending a spreadsheet with the data and computations needed to replicate our findings. Any question you might have, please do not hesitate to contact me. Thank you in advance. Please note that as per Nature's guidelines, you have 2 weeks to respond. Best regards. Luigi Mariani Universitŕ degli Studi di Milano Dept. of Crop Science Agrometeorology research group ------------------------ Luigi Mariani 329 7027077 (cellulare) 02 50316587 (Unimi-DiProVe) 02 4238410 (studio) -- **************************************************************************** Dr Nathan Gillett, Canadian Centre for Climate Modelling and Analysis, University of Victoria, PO Box 3065, STN CSC, Victoria, BC, V8W 3V6, Canada. Tel: (250) 363 8264 Fax: (250) 363 8247 Email: Nathan.Gillett@ec.gc.ca **************************************************************************** Content-Type: application/msword; name=comments_gillet_final.doc X-Attachment-Id: 0.2 Content-Disposition: attachment; filename=comments_gillet_final.doc Content-Type: application/msword; name=Mariani_response.doc X-Attachment-Id: f_foahyeac2 Content-Disposition: attachment; filename=Mariani_response.doc Prof. Phil Jones Climatic Research Unit Telephone +44 (0) 1603 592090 School of Environmental Sciences Fax +44 (0) 1603 507784 University of East Anglia Norwich Email p.jones@uea.ac.uk NR4 7TJ UK ---------------------------------------------------------------------------- ?? ? -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- MAIL: CSAG, Shell Environmental and Geographical Science Building, South Lane, Upper Campus, University of Cape Town, Private Bag X3, Rondebosch, Western Cape, 7701, South Africa TELEPHONE: +27-21-650-2999 FACSIMILE: +27-21-650-5773 E-MAIL: stoned@csag.uct.ac.za WEBPAGE: [1]http://www.csag.uct.ac.za/~daithi -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Prof. Phil Jones Climatic Research Unit Telephone +44 (0) 1603 592090 School of Environmental Sciences Fax +44 (0) 1603 507784 University of East Anglia Norwich Email p.jones@uea.ac.uk NR4 7TJ UK ----------------------------------------------------------------------------