The effect on the ITCZ and hence the monsoon and sahel is likely to be greater if the cooling isn't hemispherically balanced. This has been demonstrated in other papers,which I cannot currently be bothered to look up.
My suggestion is that we do not assume a unipolar spray pattern is safe until proven safe, and therefore we do not assume it's the likely deployed pattern - even if it is the lowest cost solution. A On 29 May 2015 17:46, "Stephen Salter" <[email protected]> wrote: > Alan > > At midsummer we have a factor of 540/440 = 1.23 for the sunshine times > 0.9 /0.25 = 3.6 for the cloud cover times 2000/200 = 10 for the boundary > layer thickness. > > This makes 44. > > The air will be cleaner too but you can estimate that. I am arguing that > a week in midsummer may be worth nearly a year at lower latitudes. But > there is no reason why a fast spray vessel cannot migrate spending a month > north of Iceland, a month at the Falklands and the rest of the time doing > whatever seems best for el Nino and the monsoons. You can see why I want a > ruggedised version of Hydroptere and get upset when people model steady > spray between + and -30 degrees latitude. They are not taking into account > one of the very attractive advantages of marine cloud brightening from fast > wind driven vessels. > > Please let me have your ideas for the ratios above. > > Stephen > > > Emeritus Professor of Engineering Design. School of Engineering, > University of Edinburgh, Mayfield Road, Edinburgh EH9 3JL, Scotland > [email protected], Tel +44 (0)131 650 5704, Cell 07795 203 195, > WWW.homepages.ed.ac.uk/shs, YouTube Jamie Taylor Power for Change > > > On 29/05/2015 13:27, Alan Gadian wrote: > > > Stephen, > > I agree with your suggested costs being < 1 billion dollars a year, given > the most expensive expectations. I do not know how the RS (2009) figures > were calculated for Marine Cloud Brightening. > > A point though is that the cooling of the poles is very well achieved > by sub-tropical solar reflection. The meridional poleward heat transport > is a major way that the system affects the polar ice reduction. The large > sub tropical area of the reflective SC clouds means that the solar energy > into the system is vastly reduced. The role of the atmosphere in the > atmospheric heat engine is to transfer heat to the poles, where the ice > melting is an important feature. Thus the MCB increased large direct > reflection near the equator, directly affects polar ice melt in a > significant manner. This is an extra critical factor c.f. the stratospheric > sulphur process. > > However, I would also agree with you that the increase in albedo near > the poles in the summer would make a significant contribution in the > cooling of the poles ... I also agree this is very important; but I would > like to emphasise that in spring, winter and autumn, a large cooling could > be achieved with sub tropical MCB. > > Thanks > Alan > > > > On Fri, 29 May 2015, Stephen Salter wrote: > > Hi All > > From http://en.wikipedia.org/wiki/Insolation the variation of > solar input with season and latitude should be > shown below. > > > [IMAGE] > > At midsummer there is about 540 watts per square metre going in to the > North pole compared with 440 going in to the > equator. In addition, around the Arctic there is a very high fraction of > low cloud cover, 80 to 90 % compared with > around 25% and a much lower boundary layer, about 200 metres so that much > less air has to be treated with salt nuclei. > The only requirements for slowing ice melt are mobility of spray vessels > and movement of air or water in a northerly > direction. > > I was a bit puzzled by Ken's mention of a few billion dollars a year for > marine cloud brightening and would like to > collect references on this. My own figures were based on index linking of > the cost of Flower class corvettes in WW II > which were build in similar numbers and suggest a few billion dollars for > a fleet which might last for 20 years or more. > Please can people send me any other cost estimates? > > However we can agree that the costs are 'in the noise'. > > Stephen > > > Emeritus Professor of Engineering Design. School of Engineering, > University of Edinburgh, Mayfield Road, Edinburgh EH9 > 3JL, Scotland [email protected], Tel +44 (0)131 650 5704, Cell 07795 203 > 195, WWW.homepages.ed.ac.uk/shs, YouTube Jamie > Taylor Power for Change > On 28/05/2015 22:38, Ronal W. Larson wrote: > List cc Ken, John Nissen, Stephen Salter > > Ken’s message re cloud brightening seems to be important . Maybe well > known to those close to the field, but I > found much new - especially between about 6 and 18 minutes in Part 4 > ( https://www.youtube.com/watch?v=b3D6mx5SQo8 ) . Nice to see credit > give to Stephen. > > Dr. Neukermans and a very few others have done a lot of impressive work > (as volunteers). His speaking style I > found convincing (including all of video #3 - none on cloud brightening). > I liked that some unpromising approaches > were also described. Only a little new (but obviously well justified) > money is now being sought. > > One question I pose on behalf of John Nissen and others in AMEG is why the > Arctic’s lack of sunlight (mentioned at > about the 18 minute mark) is critical. On an annual basis I believe the > insolation is about the world wide average > (as the sun doesn’t set for quite a few months). Not knowing enough on > the whole topic, this technical advance > would seem to be very good news for John/AMEG - if this Arctic solar issue > can still be on the table. > > There are quite a few publications on this work, with a few of the most > recent at > > > https://www.researchgate.net/publication/260755971_Sub-micrometer_salt_aerosol_production_intended_for_marine_cloud_brig > htening > > > http://www.economist.com/news/science-and-technology/21635983-scientific-studies-techniques-deliberately-modifying-clima > te-are > > > http://articles.latimes.com/2014/mar/04/nation/la-na-climate-engineering-20140305/2 > > Ron > > > > On May 28, 2015, at 9:04 AM, Ken Caldeira <[email protected]> > <[email protected]> wrote: > > Five YouTube videos of the 12 May event are available here: > https://www.youtube.com/playlist?list=PL4E3D946BECCF7DE3 > > The event is described here: > > > http://www.sri.com/newsroom/events/cafe-scientifique-silicon-valley-sri-two-novel-approaches-mitigating-climate-change > > Part 1: Ken on solar geo and strat aerosols: > https://www.youtube.com/watch?v=-Y6p-B-KbiQ > Part 2: Ken on solar geo and strat aerosols: > https://www.youtube.com/watch?v=wo5Y-SPrybE > Part 3: Armand on marine cloud brighening: > https://www.youtube.com/watch?v=ZbpYGwu4KNA > Part 4: Armand on marine cloud brighening: > https://www.youtube.com/watch?v=b3D6mx5SQo8 > Part 5: Ken and Armand answer questions: > https://www.youtube.com/watch?v=9KS9Nbe3Wzs > > Cafe Scientifique Silicon Valley @ SRI: Reflecting Sunlight to Cool > Earth's Climate: Emulating Volcanoes and > Brightening Marine Clouds > > May 12, 2015 > SRI - Menlo Park, CA > > This free Cafe event will feature presentations by two thought leaders on > climate change: > > Caldeira and Neukermans > Ken Caldeira (l); Armand Neukermans (r) > > Solar Geoengineering and Climate Change: Nearly everyone understands that > the most effective way to reduce > environmental risk associated with climate change is to deeply cut > greenhouse gas emissions as soon as > possible, yet emissions and atmospheric concentrations of greenhouse gases > continue to increase. If current > emissions trends continue, by the end of this century, nearly every summer > in the tropics will be hotter than > the hottest summer yet on record, raising the possibility of widespread > crop failures and famine. If climate > change does prove truly catastrophic, the only feasible way to cool the > Earth rapidly would be to use solar > geoengineering technologies, for example, by emulating the cooling effects > of volcanoes. While it is fairly > certain that Earth's climate can be cooled in this way, it is far less > certain whether such approaches could > ever really reduce overall risk and damage. Dr. Ken Caldeira, a senior > climate scientist at the Carnegie > Institution for Science, will present the science of solar geoengineering > and discuss what this science might > mean for society. > > Marine Cloud Brightening: The National Academy of Sciences recently called > for research into > “geoengineering“. Dr. Armand Neukermans will describe the efforts of a > group of retired scientists and > engineers to develop a spray system that might enable a study of the > feasibility of marine cloud brightening > (MCB) for climate cloud studies, as well as possible climate intervention. > MCB aims to increase the > reflectivity of low-hanging ocean clouds, thereby reflecting more sunlight > and cooling the planet. This might > be done by increasing the droplet concentration in the clouds by spraying > seawater from oceangoing ships. The > proposed systems aims to create 1015 cloud nuclei from a glass of > seawater. MCB ( if ever needed) might > conceivably be used globally or locally (e.g., for arctic melt shielding, > hurricane cooling, reef > preservation, or fog belt restoration). > > About the Speakers > > Dr. Ken Caldeira is a climate scientist working for the Carnegie > Institution for Science, Department of > Global Ecology at Stanford University. He investigates issues related to > climate, carbon, and energy systems. > His primary tools are climate and the carbon cycle models, although he > does field work related to ocean > acidification. Dr. Caldeira co-authored a recent National > Academies report, Climate Intervention: Reflecting > Sunlight to Cool Earth. A free PDF version is available. > > Dr. Armand Neukermans has held research and management positions at > KLA-Tencor, Hewlett-Packard, Xerox, and > General Electric, and founded Xros, an optical switch company. He is the > author of 40 publications and the > inventor of more than 75 patents in diverse fields. He was named Silicon > Valley “Inventor of the year” in > 2001. Since his retirement, he has been involved in environmental > projects, such as the foundation of the Big > Sur Environmental Institute, and in fostering the causes of social > entrepreneurs. He holds EE and ME degrees > from Louvain University, and a Ph.D. in applied physics from Stanford > University. > > - See more at: > http://www.sri.com/newsroom/events/cafe-scientifique-silicon-valley-sri-two-novel-approaches-mitigating-climate-change#s > thash.S562iCyX.dpuf > > > _______________ > Ken Caldeira > > Carnegie Institution for Science Dept of Global Ecology > 260 Panama Street, Stanford, CA 94305 USA > +1 650 704 7212 [email protected] > website: http://dge.stanford.edu/labs/caldeiralab/ > blog: http://kencaldeira.org > @KenCaldeira > > My assistant is Dawn Ross <[email protected]> > <[email protected]>, with access to incoming emails. > Postdoc positions: > https://jobs.carnegiescience.edu/jobs/postdoctoral-opportunity-global-climate-modeling/ > > > -- > 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. > > > -- > 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. > > > -- > 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. > > > > > -- > 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. > > The University of Edinburgh is a charitable body, registered in > Scotland, with registration number SC005336. > > -- > 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. > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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