Hi Stephen, Thanks – yes I agree there are lots of other things that vary. The idea with the poster was just to show an example of the effect from differences in background CCN. I agree there’s lots of other interesting things that would cause regional variations too. And those would be very interesting to investigate too . Cheers Graham
From: Stephen Salter [mailto:[email protected]] Sent: 30 July 2015 13:06 To: Graham Mann; [email protected] Subject: Re: [geo] 2 quick questions for Social scientists, humanities researchers, philosophers of SRM Hi Graham But why did you study only two regions and only an increase in aerosol? In a computer is just as easy to reduce them which would keep the world wide value steady. While the ones you picked are probably the best for all-year spray they will not be so good once you have increased the CCN concentration and there may be others which are nearly as good. For example around mid-summer the long hours of sunshine, the high fraction of cloud cover, the clean air and the low boundary layer might make the Barents Sea and the Aleutians even better in June and July however bad they might be in December and January when the spray vessels will have all migrated to the Antarctic. It is also scientifically interesting to know where the useless places and seasons are. With coded modulation you do not need to do different runs for everywhere. You can do just one long run and then select seasonal subsets and Boolean combinations. The correlation process is almost instantaneous. Next you could vary the spray patterns in the light of the actual model results to close a feedback loop. My engineer's guess for the most promising control variables will be the temperature differences across the Indian and Pacific Oceans but with coded modulation you have a good chance to discover others. Stephen Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JL, Scotland [email protected]<mailto:[email protected]>, Tel +44 (0)131 650 5704, Cell 07795 203 195, WWW.homepages.ed.ac.uk/shs<http://WWW.homepages.ed.ac.uk/shs>, YouTube Jamie Taylor Power for Change On 30/07/2015 11:27, Graham Mann wrote: Hi Stephen, Re: your comment: > I would be most grateful for information about where and when the technology > should NOT be used. One thing is that the efficacy of the injection (just in terms of radiative forcing) various considerably between different regions. The radiative effects for a given increase in CCN depend strongly on the background CCN concentration in the region. That’s partly because the cloud droplet number concentration (CDNC) against CCN curve is non-linear. And also because it’s the relative CDNC change that is important for the brightening effect (rather than the absolute change). So the same change in tropospheric CCN translates into quite different radiative forcing in different regions. Some work by Ben Parkes and others at Leeds (currently unpublished) that we presented at EGU 2013 (see attached) demonstrates this effect. For example we see that injecting sea-spray in the North Pacific stratocumulus region is 3-4 times less effective than in injecting in the South Pacific Sc region. And that both regions saturate for increasing injection of sea-spray. Cheers Graham ** Dr. Graham Mann, NCAS Senior Research Scientist ** ** Institute for Climate & Atmospheric Science T: +44 0113 3431660 ** ** Room 10.108, School of Earth & Environment F: +44 0113 3435259 ** ** University of Leeds, Leeds, LS2 9JT, U.K. E: [email protected]<mailto:[email protected]> ** From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Stephen Salter Sent: 30 July 2015 10:28 To: [email protected]<mailto:[email protected]> Subject: Re: [geo] 2 quick questions for Social scientists, humanities researchers, philosophers of SRM Pete, Thank you for you request. The one thing I would like is the production of world-wide seasonal maps of the susceptibility with respect to temperature and precipitation to changes in the concentration of tropospheric cloud condensation nuclei from everywhere to everywhere else. I hope that the coded modulation idea in the attached paper might be useful but perhaps you can think of better ways. A 1.6 Mb paper is attached but, if it is chopped, I can send it directly to anyone who emails me I would be most grateful for information about where and when the technology should NOT be used. Stephen Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JL, Scotland [email protected]<mailto:[email protected]>, Tel +44 (0)131 650 5704, Cell 07795 203 195, WWW.homepages.ed.ac.uk/shs<http://WWW.homepages.ed.ac.uk/shs>, YouTube Jamie Taylor Power for Change On 30/07/2015 10:05, p.j.irvine wrote: Hi all, As you might know, I work primarily on the climate response to SRM and I'd like to know how we can better understand the implications of SRM and how those implications will depend on what we discover about its likely consequences. So if you have the time, I'd like all you social scientists, humanities researchers and philosophers of SRM to answer these 2 questions: 1) With regards to its consequences, what one thing would help you to better understand the implications of SRM for your area of interest? 2) What one thing do you wish that those of us working on the physical consequences of SRM would bear in mind? These don't have to be easily achievable and feel free to be controversial but I'd like to get a taste for what people feel we'll need to do to understand this issue better. Cheers, Pete -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
