The ITCZ does not effectively mix air from both N and S tropospheres. The tracer content of the lower stratosphere between the Arctic and the Antarctic showed this, especially the CO distribution, during the ASHOE/MAESA ER-2 mission in 1994. The SH LS is fed mainly from the SH troposphere, and the same applies to the NH.
Adrian Tuck 'ATMOSPHERIC TURBULENCE: A Molecular Dynamics Perspective'. Oxford University Press, 2008. ISBN 978-0-19-923653-4. http://www.oup.com/uk/catalogue/?ci=9780199236534 *************************************************** On 30 May 2015, at 00:21, Andrew Lockley <[email protected]> wrote: > 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]> >>> 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]>, 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. > 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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