date: Mon, 13 Jun 2005 17:08:01 +0200 from: Hugues Goosse subject: Re: IPCC AR4 model runs of last 1000 years to: Tim Osborn Dear Tim, The figures appear fine for me. The forcing we are using for Ozone reaches about 0.4 W/m2. If you add the weak radiative forcing of aerosols, it make more or less the differences with the others. ECBILT has a quite low sensitivity (in particular, the response is weak in the tropics, with a large impact at global scale, the response is more in agreement with other models in mid and high latitudes). That explains probably why the response is weak despite the larger forcing. All the best Hugues At 15:07 13/06/2005 +0100, you wrote: >Hugues, > >please see attached figure. Still in progress - more lines to add, plus >legend is incomplete. > >You were right that Crowley et al. (2003) use SO4 aerosol forcing that >reaches about -1 W/m2 by 2000. The lower value I told you comes from some >of their newer simulations! > >Your data are a dirty yellow colour. (c) shows "all other forcings" which >should include everything except volcanic and solar irradiance. You will >see that ECHO-G (red) is highest from 1850 to late 1900s, as expected >because of no SO4 cooling. But your data catch up and reach ECHO-G by >1990, despite SO4 cooling and land-use cooling. Hence your GHGs are >stronger (ECHO-G GHG was +1.8 W/m2 in 1990). They include only CO2, CH4 >and N2O. Maybe that explains it? > >Anyway, I think (hope) that everything is correct, but I would be please >if you could check that the "Goosse2005" series look right. > >Cheers > >Tim > > >At 11:18 13/06/2005, you wrote: >>Yes, it is the direct forcing applied in the model (TSI changes) not the >>forcing at the tropopause. >> >>Cheers >> >>Hugues >> >>At 09:55 13/06/2005 +0100, you wrote: >>>At 08:28 02/06/2005, you wrote: >>>>Hi Tim, >>>> >>>>I have attached the file I send to Pascale. It includes Solar forcing, >>>>volcanic forcing, >>> >>>Dear Hugues, >>> >>>a quick question - is the solar forcing the irradiance change, and thus >>>should I multiply by 0.25*(1-albedo) to convert to a forcing comparable >>>to GHG forcing? >>> >>>Cheers >>> >>>Tim >>> >>> >>> >>>Dr Timothy J Osborn >>>Climatic Research Unit >>>School of Environmental Sciences, University of East Anglia >>>Norwich NR4 7TJ, UK >>> >>>e-mail: t.osborn@uea.ac.uk >>>phone: +44 1603 592089 >>>fax: +44 1603 507784 >>>web: http://www.cru.uea.ac.uk/~timo/ >>>sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm >> >> -------------------------------------- >>GOOSSE Hugues >>http://www.astr.ucl.ac.be/users/hgs/index.html >>Institut dAstronomie et de Géophysique G. Lemaître >>Université catholique de Louvain , Chemin du cyclotron, 2 >>1348 Louvain-la-Neuve, Belgium >> >>e-mail: hgs@astr.ucl.ac.be > > > >Dr Timothy J Osborn >Climatic Research Unit >School of Environmental Sciences, University of East Anglia >Norwich NR4 7TJ, UK > >e-mail: t.osborn@uea.ac.uk >phone: +44 1603 592089 >fax: +44 1603 507784 >web: http://www.cru.uea.ac.uk/~timo/ >sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm -------------------------------------- GOOSSE Hugues http://www.astr.ucl.ac.be/users/hgs/index.html Institut dAstronomie et de Géophysique G. Lemaître Université catholique de Louvain , Chemin du cyclotron, 2 1348 Louvain-la-Neuve, Belgium e-mail: hgs@astr.ucl.ac.be