30 hPa is about 25kms. That's pretty normal for release studies. See for example Aurora flight services report
I'm doing a paper at present which shows you can loft a shell that high for very little money - probably an order of magnitude cheaper than Aurora calculated. I've not finished the calcs yet. You could hit those costs using an extended Mark 7 Iowa class 16 in gun. Methane/air propellant should get you to 25k, but using a H2 / O2 propellant (run rich) can get far higher by improving speed of sound. To cut shell mass you can use an enlarged, fin-stabilized aluminum or titanium shell. Projectiles would splashdown, to be reused or scrapped. A On Jun 29, 2012 4:33 PM, "Simone Tilmes" <[email protected]> wrote: > Dear Ken, > > thanks a lot to Matthias, to translate the article! > > I think it is important to point out that there is very likely a limit on > how much the Earth's surface could be cooled using sulfate aerosols, due to > coagulation processes and fall out of aerosols. Only less than 2 W/m2 > reduction of global net surface SW flux was achieved in the study by > Heckendorn et al., 2009, using a micro-physical model to consider size > distributions of the aerosols. Niemeier et al., 2010, achieved a stronger > forcing if injecting particles at 30hPa, which allow them to stay longer in > the stratosphere. Though it will be hard to inject particles that high. > > Cheers, Simone > > References: > Niemeier, U., H. Schmidt and C. Timmreck, The dependency of geoengineered > sulfate aerosol on the emission strategy, Atmos. Sci. Let., DOI: > 10.1002/asl.304, 2010. > > Heckendorn P, Weisenstein D, Fueglistaler S, Luo BP, Rozanov E, Schraner > M, Thomason LW, Peter T. 2009. The impact of geoengineering aerosols on > stratospheric temperature and ozone. > Environmental Research Letters 4: 045108. DOI: > 10.1088/1748-9326/4/4/045108. > > > > Simone, >> >> Not reading German, I don't know precisely what is in the story. >> >> What I said to the reporter is that if the aerosol layer similar to that >> of Mt Pinatubo were sustained, it would produce a cooling of about 3 K. >> >> This is based on estimates of Mt Pinatubo producing around 4 W / m2 of >> radiative forcing (cf. Crutzen, 2006?), which is similar to a CO2 >> doubling -- and 3 C per CO2 doubling is in the middle of the range of >> estimates for climate sensitivity. So, this is just a back-of-envelope >> calculation. >> >> A question of course, given particle aggregation and so on, is whether >> such a layer could be sustained. >> >> Best, >> >> Ken >> >> >> On Thu, Jun 28, 2012 at 6:37 PM, Simone Tilmes <[email protected] >> <mailto:[email protected]>> wrote: >> >> Dear Ken, >> >> in the article you stated that Mt Pinatubo is assumed to result in a >> global cooling of about 0.5 degree. It is also stated in the text of >> the article that the amount of aerosols emitted, if they would stay >> in the stratosphere for a longer time period, would result in a 3 >> degrees global cooling. Could you point me to the study you are >> referring to that calculates this amount of cooling if injecting >> volcanic aerosols of the amount of Mt Pinatubo? >> >> Cheers, Simone >> >> >> Ken >> >> It should follow from your argument about the land-sea temperature >> difference reducing precipitation on land that a technique which >> had the >> initial effect of cooling the sea would be more attractive. If >> it were >> also possible to have a frequency response shorter than the monsoon >> cycle we could play useful tricks about the phase of operations >> relative >> to the monsoon season. >> >> Stephen >> >> Emeritus Professor of Engineering Design >> Institute for Energy Systems >> School of Engineering >> Mayfield Road >> University of Edinburgh EH9 3JL >> Scotland >> Tel +44 131 650 5704 <tel:%2B44%20131%20650%205704> >> Mobile 07795 203 195 >> www.see.ed.ac.uk/~shs <http://www.see.ed.ac.uk/~shs> >> >> >> On 28/06/2012 06:27, Ken Caldeira wrote: >> >> pdf attached. >> >> http://www.nzz.ch/wissen/__**wissenschaft/sonnenschutz-__** >> fuer-die-erde-1.17282213<http://www.nzz.ch/wissen/__wissenschaft/sonnenschutz-__fuer-die-erde-1.17282213> >> <http://www.nzz.ch/wissen/**wissenschaft/sonnenschutz-** >> fuer-die-erde-1.17282213<http://www.nzz.ch/wissen/wissenschaft/sonnenschutz-fuer-die-erde-1.17282213> >> > >> >> >> _______________ >> Ken Caldeira >> >> Carnegie Institution for Science >> >> Dept of Global Ecology >> 260 Panama Street, Stanford, CA 94305 USA >> +1 650 704 7212 <tel:%2B1%20650%20704%207212> >> [email protected] >> >> <mailto:kcaldeira@**carnegiescience.edu<[email protected]> >> > >> >> <mailto:kcaldeira@__carnegiesc**ience.edu<http://carnegiescience.edu> >> >> <mailto:kcaldeira@**carnegiescience.edu<[email protected]> >> >> >> >> http://dge.stanford.edu/labs/_**_caldeiralab<http://dge.stanford.edu/labs/__caldeiralab> >> >> <http://dge.stanford.edu/labs/**caldeiralab<http://dge.stanford.edu/labs/caldeiralab>> >> @kencaldeira >> >> *Currently visiting * Institute for Advanced Sustainability >> Studies >> (IASS) <http://www.iass-potsdam.de/> >> *and *Potsdam Institute for Climate Impact Research (PIK) >> <http://www.pik-potsdam.de/>*_**_in Potsdam, Germany.* >> >> >> -- >> You received this message because you are subscribed to the >> Google >> Groups "geoengineering" group. >> To post to this group, send email to >> geoengineering@googlegroups.__**com >> >> <mailto:geoengineering@**googlegroups.com<[email protected]> >> >. >> To unsubscribe from this group, send email to >> >> geoengineering+unsubscribe@__g**ooglegroups.com<http://googlegroups.com> >> >> <mailto:geoengineering%**[email protected]<geoengineering%[email protected]> >> **>. >> For more options, visit this group at >> >> http://groups.google.com/__**group/geoengineering?hl=en<http://groups.google.com/__group/geoengineering?hl=en> >> >> <http://groups.google.com/**group/geoengineering?hl=en<http://groups.google.com/group/geoengineering?hl=en> >> >. >> >> >> >> 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 post to this group, send email to >> geoengineering@googlegroups.__**com >> <mailto:geoengineering@**googlegroups.com<[email protected]> >> >. >> To unsubscribe from this group, send email to >> geoengineering+unsubscribe@__g**ooglegroups.com<http://googlegroups.com> >> >> <mailto:geoengineering%**[email protected]<geoengineering%[email protected]> >> **>. >> For more options, visit this group at >> >> http://groups.google.com/__**group/geoengineering?hl=en<http://groups.google.com/__group/geoengineering?hl=en> >> >> <http://groups.google.com/**group/geoengineering?hl=en<http://groups.google.com/group/geoengineering?hl=en> >> >. >> >> >> > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to > geoengineering@googlegroups.**com<[email protected]> > . > To unsubscribe from this group, send email to geoengineering+unsubscribe@* > *googlegroups.com <geoengineering%[email protected]>. > For more options, visit this group at http://groups.google.com/** > group/geoengineering?hl=en<http://groups.google.com/group/geoengineering?hl=en> > . > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
