Maybe we are talking about two different things then. Maybe there should be one set of semi-realistic simulations for the CMIP5 modelers and another set of standard simple and idealized, but helpful, reference simulations for people to do (as a courtesy to the community) if they are planning to spend more time doing climate intervention simulations.
Frankly, even for the CMIP5 modelers, I think we would learn more from very simple and idealized simulations that we would learn from complex "realistic" simulations, although both are valuable. ___________________________________________________ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA kcalde...@carnegie.stanford.edu http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab +1 650 704 7212; fax: +1 650 462 5968 On Tue, Dec 8, 2009 at 1:20 PM, Alan Robock <rob...@envsci.rutgers.edu>wrote: > Dear Ken, > > Thanks for your comments. I agree that multiple experiments like you > outline would be interesting, but the CMIP5 modelers made it clear that they > are very busy with all the other agreed-on runs, and would only have time > for a very small number of geoengineering runs. That is why we decided to > make it very simple and have a small number of runs. > > The standard suite of parameters will be archived at PCMDI along with all > the other CMIP5 runs, and this set has been standard for quite some time. > You can look at the AR4 archive for more details. > > A preliminary version was already presented to the WGCM meeting in > September, and if the modelers agree, PCMDI is onboard. > > > Alan > > Alan Robock, Professor II > Director, Meteorology Undergraduate Program > Associate Director, Center for Environmental Prediction > Department of Environmental Sciences Phone: +1-732-932-9800 x6222 > Rutgers University Fax: +1-732-932-8644 > 14 College Farm Road E-mail: rob...@envsci.rutgers.edu > New Brunswick, NJ 08901-8551 USA > http://envsci.rutgers.edu/~robock<http://envsci.rutgers.edu/%7Erobock> > > > On Tue, 8 Dec 2009, Ken Caldeira wrote: > > Folks, >> >> This is a good first start, but ... >> >> I am a big believer in specifying some very simple idealized experiments >> in >> that I think these are often the easiest to analyze and the most >> illuminating regarding system behavior. >> >> It is often good to change one thing at a time so that it is easy to >> analyze >> how the system responds to different perturbations. >> >> I think it is also good to recognize that different people are doing >> simulations in different kinds of models that include different kinds of >> processes, and these different kinds of models have utility for different >> kinds of applications. >> >> So, I think it would describe a suite of experiments: >> >> 1. Step function change in atmospheric CO2 concentration. >> 2. Step function change in solar constant (perhaps decrease). >> 3. Combined step function change in atmospheric CO2 concentration + solar >> constant (= 1+2) >> 4. Step function change in specified aerosols distribution and >> concentrations >> 5. Combined step function change in atmospheric CO2 concentration and >> aerosol distribution and concentration (=1 + 4) >> 6. Unit pulse of stratospheric aerosol emissions >> 7. Step function change in stratospheric aerosol emissions (ie, continuous >> emissions) >> 8. Combined step function change in atmospheric CO2 concentration and >> aerosol emissions (=1+7) >> >> Following these I would have the experiments described in the document >> that >> Alan sent around. Groups could do as many of these as that are relatively >> easy to do. >> >> In analyzing the differences between the more complex runs, these simpler >> runs will prove extremely useful. For example, it will show whether the >> differences in the model response is due to model response to a specified >> aerosol distribution or whether the difference is because the model >> produces >> a different distribution from the same emissions. >> >> This will also allow groups who are unable to do the full suite of runs to >> at least do these simplified experiments to allow a common basis for >> comparison of a broader range of models. >> >> Also, a major piece missing from the document is the specification of what >> model output is required. >> >> Before going too far with this, I would consult with people from PCMDI who >> were involved in analyzing AR4 results, and I would also consult with Jim >> Orr who led the ocean carbon-cycle model intercomparison program (OCMIP). >> One problem with C4MIP (the coupled carbon climate MIP) is that not enough >> data was collected from each group to allow for adequate analysis of >> results. >> >> I believe that it is often the simplest simulations that teach you the >> most. >> >> >> Best, >> >> Ken >> >> >> >> >> >> ___________________________________________________ >> Ken Caldeira >> >> Carnegie Institution Dept of Global Ecology >> 260 Panama Street, Stanford, CA 94305 USA >> >> kcalde...@carnegie.stanford.edu >> http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab >> +1 650 704 7212; fax: +1 650 462 5968 >> >> >> >> >> On Tue, Dec 8, 2009 at 1:46 AM, Alan Robock <rob...@envsci.rutgers.edu >> >wrote: >> >> Dear All, >>> >>> After extensive discussion of our original proposal by email and at a >>> geoengineering workshop in Hamburg a week ago, I attach our final >>> proposal for standardized geoengineering experiments. As Atm. Research >>> Letters will have a special geoengineering issue, we have written it for >>> possible submission. >>> >>> In any case, I hope this will allow climate modeling groups and others >>> to look at it and comment, and we welcome all such comments. >>> >>> Alan >>> >>> Alan Robock, Professor II >>> Director, Meteorology Undergraduate Program >>> Associate Director, Center for Environmental Prediction >>> Department of Environmental Sciences Phone: +1-732-932-9800 x6222 >>> Rutgers University Fax: +1-732-932-8644 >>> 14 College Farm Road E-mail: rob...@envsci.rutgers.edu >>> New Brunswick, NJ 08901-8551 USA >>> http://envsci.rutgers.edu/~robock<http://envsci.rutgers.edu/%7Erobock> >>> <http://envsci.rutgers.edu/%7Erobock> >>> >>> >>> -- >>> >>> You received this message because you are subscribed to the Google Groups >>> "Climate Intervention" group. >>> To post to this group, send email to >>> climateintervent...@googlegroups.com. >>> To unsubscribe from this group, send email to >>> climateintervention+unsubscr...@googlegroups.com<climateintervention%2bunsubscr...@googlegroups.com> >>> <climateintervention%2bunsubscr...@googlegroups.com<climateintervention%252bunsubscr...@googlegroups.com> >>> > >>> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/climateintervention?hl=en. >>> >>> >>> >>> >> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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