cc: myles , Tim Barnett , Nathan Gillett , Phil Jones , David Karoly , Jesse Kenyon , Reto Knutti , Tom Knutson , Toru Nozawa , Doug Nychka , Claudia Tebaldi , Ben Santer , Richard Smith , Daithi Stone , "Stott, Peter" , Michael Wehner , Xuebin Zhang , francis , Hans von Storch , Karl Taylor date: Mon, 28 May 2007 02:11:43 -0500 from: David Karoly subject: Re: 5AR runs next iteration- reply by 26th to: Gabi Hegerl Hi Gabi, First of all, apologies for the late reply but I wanted to let everyone know that I am now based at the University of Melbourne now, having finished at OU on May 15. My contact details are below. Please update your address book by deleting my ou email address and inserting my Melb Uni email address. Thanks. I have a few comments on the email exchanges but I agree with many comments. Start date: This is likely to be a compromise between length of past run, number of ensemble members and length of run into the future. We need to stress the point that longer runs ie starting in 1950 will be better for attribution and start-up issues. Of course, this may lead to fewer members in the ensembles, but I am not sure which is better. Control runs/ensemble size/estimating internal variability: I agree with Daithi that we need a control to estimate climate drift of the hi-res coupled models and to check whether the lower-res coupled models have similar drift. Given enough ensemble members and long enough runs, we may be able to estimate decadal timescale variability from inter-member differences, but I don't know how many enough is. I would rather have more ensemble members than a 200-500 year hi-res control run, as we can get information about both the forced response and the variability from large ensembles, at least in principle. Variables saved: As Karl has said, many of the monthly variables listed were requested or are available in the CMIP3 archive, listed at http://www-pcmdi.llnl.gov/ipcc/standard_output.html However, some of the variables below should be requested or increased in importance, as they weren't commonly available in teh CMIP3 database. Monthly mean surface Tmin (tasmin), Tmax (tasmax), specific humidity (huss) Daily mean surface specific humidity (huss) (Tmin and Tmax already available) These will be useful for impacts assessments including for wild fire and heat stress, as well as to make use of a new observed humidity dataset. For another project, I am using 6 hourly full vertical resolution 3-D fields for all variables. It is too much to ask for this from all models but I hope that some models will archive these data for some 10 year time periods, if only to allow nesting of regional climate models and other diagnostic projects. Best wishes, David -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NOTE: New address from May 16, 2007 Prof David Karoly School of Earth Sciences, University of Melbourne, VIC 3010, AUSTRALIA ph: +61 3 8344 4698 fax: +61 3 8344 7761 email: dkaroly@unimelb.edu.au ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Quoting Gabi Hegerl : > Hi all. > > From your comments, I assembled a word file with our suggestions on the > 5AR run > proposal, but I am not sure > I caught it all completely. Also, I had a chat with Jerry yesterday, and > he said getting > suggestions of what should be stored will be useful at this point. > My plan is to communicate this with Jerry when we are done with it, and > then propose > it at the WGCM meeting. > > I drew a strawman list of what I could think of in 3 minutes, and am > asking you to > add to it. Its all in track changes, so dont hesitate to go wild (but > please keep in mind that > we need to restrict data requests to something you think you will work > with in the next > years, since it is a fair amount of effort from the modelling centres to > haul the data over > etc, and the more we request, the more likely it is that only few > ensemble members etc > get sent...) > > Karl, I am cc;ing you since your perspective would be useful > > Gabi > > -- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Gabriele Hegerl > Division of Earth and Ocean Sciences, > Nicholas School for the Environment and Earth Sciences, > Box 90227 > Duke University, Durham NC 27708 > Ph: 919 684 6167, fax 684 5833 ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.