cc: plattner@climate.unibe.ch, Jonathan Overpeck , Stefan Rahmstorf , Anders Levermann , Eva Bauer , Eystein Jansen , t.osborn@uea.ac.uk, joos date: Tue, 21 Feb 2006 09:20:37 -0700 from: Jonathan Overpeck subject: Re: Fwd: Re: Millennium Simulations to: Keith Briffa Many thanks. >now working on stitching all bits together (thanks Fortunat for your >text) - and , (other than final refs which are a mess!) the 2000 >year section should come by tomorrow evening my time - still having >to juggle University and teaching/committee crap) . Keith > > >At 16:33 20/02/2006, Tim Osborn wrote: >>Dear all, >> >>after talking with Keith about the exact wording to use in the text >>to describe how the stronger solar forcing assumption raises the >>variability of the simulated temperatures, I've realized that it >>might be misleading to say that the standard deviation of natural >>variability of NH temperature is 58-72% higher if the strong solar >>forcing is assumed than if the weak solar forcing is assumed. The >>reason is that these figures refer only to the natural variability >>that is *forced* (unless these models have internally-generated >>variability -- inspection of the control runs for Bern2.5CC and >>Climber2 suggests that they don't). If internally-generated >>variability had a standard deviation (for 30-year smoothed NH >>temperatures) of, say, 0.08 K (from HadCM3), then the stronger >>solar case would have total natural variability only 28-40% greater >>than the weaker solar case. >> >>Is this right? If so, should we just change the text to indicate >>that we only mean natural variability due to external forcings? >> >>Cheers >> >>Tim >> >>At 15:23 20/02/2006, Fortunat Joos wrote: >>>Thanks Tim. This sounds good. >>> >>>Tim Osborn wrote: >>>>At 15:23 15/02/2006, Fortunat Joos wrote: >>>> >>>>>TIM can you please give us the appropriate number for the >>>>>low-freq. NH T variability and specify the smoothin. >>>> >>>>Hi Fortunat, >>>>for the smoothing actually used on the Climber2/3a/Bern2.5CC >>>>figure (30-year smoothing), these are the standard deviations of >>>>the simulated NH temperatures for the "only natural forcings >>>>runs": >>>> Bard08-WLS Bard25 Ratio of standard deviations >>>>Bern 0.103 0.177 1.72 >>>>Clm2 0.078 0.123 1.58 >>>>Clm3a 0.092 0.147 1.60 >>>>So, the multi-decadal variability in NH surface air temperature >>>>is between 58% and 72% greater under the stronger solar forcing >>>>(Bard25) than under the weaker solar forcing (Bard08-WLS). >>>>This can go in the text where Fortunat indicated. OK everyone? >>>>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 >>> >>>-- >>> >>> Climate and Environmental Physics, >>> Physics Institute, University of Bern >>> Sidlerstr. 5, CH-3012 Bern >>> Phone: ++41(0)31 631 44 61 Fax: ++41(0)31 631 87 42 >>> Internet: http://www.climate.unibe.ch/~joos/ >> >>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 > >-- >Professor Keith Briffa, >Climatic Research Unit >University of East Anglia >Norwich, NR4 7TJ, U.K. > >Phone: +44-1603-593909 >Fax: +44-1603-507784 > >http://www.cru.uea.ac.uk/cru/people/briffa/ -- Jonathan T. Overpeck Director, Institute for the Study of Planet Earth Professor, Department of Geosciences Professor, Department of Atmospheric Sciences Mail and Fedex Address: Institute for the Study of Planet Earth 715 N. Park Ave. 2nd Floor University of Arizona Tucson, AZ 85721 direct tel: +1 520 622-9065 fax: +1 520 792-8795 http://www.geo.arizona.edu/ http://www.ispe.arizona.edu/