date: Wed Aug 3 09:08:34 2005 from: Phil Jones subject: Re: pairing of model runs... to: alex@gvc.gu.se Alex, OK, my misunderstanding. Treat each as a separate run then. Makes life easier. Cheers Phil At 18:12 01/08/2005, you wrote: Hi Phil, I asked Jeff Knight for assistance regarding pairing of model runs. The model runs seem to be not available in pairs as I understood his answer. See his answer below. So I'll continue with applying the extremes rountine on each single run (start with one "anthro+nat" and one "nat")?. =========================================== ... There is no sense in which the runs are paired. The experimental design is this: We perform a 1-year spin-up run for each ensemble member starting 1st December 1868. We use initial atmospheric conditions from a coupled run of HadCM3 for circa 1870 conditions. Different initial conditions are used for each member. By the end of the spin-up calculations, the initial conditions are forgotten, as the atmosphere on its own has memory for only a few months. The atmospheric states at 1st December 1869 are a combination of the response to the climate forcing factors (SST, GHG etc, and the same for all ensemble members) and a random component (which varies between ensemble members), such that each ensemble member starts with a different plausible state. We then perform the runs from 1st December 1869 to obtain the final results that are published on the web site. The ensemble members represent independent realisations of the 'weather noise' but with a consistent forced component. As such there is no pairing between ensembles as the 1/12/1869 conditions are unique for each and every run performed. I hope this helps. Please ask if you need any more information. Jeff PS. The remaining 3 all forcings and 2 natural runs will soon be added to the site. We are just awaiting resolution of a technical difficulty in getting more disk space added to the server. ================================================= regards Alex -- *************************** Alexander Walther Earth Sciences Centre Göteborg University Box 460 S-405 60 Göteborg, Sweden --------------------------- Fon: (+46)-31-7734849 Fax: (+46)-31-7731986 [1]http://www.gvc.gu.se/rcg *************************** 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 ----------------------------------------------------------------------------