Oliver and List, The primary cloud condensate nuclei for type one polar stratospheric clouds is sulfuric acid. This is a well known and established fact found in atmospheric physics.
Here I offer a few reference among the many available: 1) Theoretical and Modeling Studies of the Atmospheric Chemistry of Sulfur: Hazem S. El-Zanan The relevance of the above book, to this topic, is found within the introduction. 2) A 2D microphysical model of the polar stratospheric CN layer <http://onlinelibrary.wiley.com/doi/10.1029/1999GL900187/abstract> 1. Michael J. Mills1, 2. Owen B. Toon1and 3. Susan Solomon2 *"Each spring a layer of small particles forms between 20 and 30 km altitude in the polar regions. We present the first self-consistent explanation of the observed “CN layer” from a 2D microphysical model of sulfate aerosol. Our theory relies on photolysis of H2SO4 and SO3, consistent with recent laboratory measurements, to produce SO2 in the upper stratosphere and mesosphere. An additional source of SO2may be required. Nucleation throughout the polar winter extends the top of the aerosol layer to higher altitudes, despite strong downward transport of ambient air. This may affect heterogeneous chemistry at the top of the aerosol layer in polar winter and spring.".* Please pay close attention to the '*Particle Microphysics*' section and the conclusion in the above paper. Further, if we take a close look at the '*Pinatubo Effect*', in relationship to ozone production with elevated SO2 levels, we find a significant downward trend in the "*global mean column ozone*". This scenario is explained in the following paper. Please see pg. 403, 2nd column, 4th-5th para.: 3) Atmospheric effects of the Mt. Pinatubo eruption <http://www.nuclear.lu.se/fileadmin/nuclear/Undervisning/Atmosfaerskurs/P04.pdf> : MP McCormick, LW Thomason, CR Trepte - Nature, 1995 However, we can find reference to the apparent contradictions found in the premise that SAI offers no threat to polar stability while lowering the 'global average temperature' in a far more topical references...such as: 4) Polar stratospheric cloud <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#Types> (Wiki) PSCs are classified into three types Ia, Ib and II according to their chemical composition <http://en.wikipedia.org/wiki/Chemical_composition> which can be measured using LIDAR <http://en.wikipedia.org/wiki/LIDAR>. The technique also determines the height and ambient temperature of the cloud.[4] <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> - Type I clouds contain water, nitric acid <http://en.wikipedia.org/wiki/Nitric_acid> and/or sulfuric acid <http://en.wikipedia.org/wiki/Sulfuric_acid> and they are a source of polar ozone depletion <http://en.wikipedia.org/wiki/Ozone_depletion>.[5] <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-5> - Type Ia clouds consist of large, aspherical particles, consisting of nitric acid trihydrate (NAT).[4] <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> - Type Ib clouds contain small, spherical particles (non-depolarising), of a liquid supercooled <http://en.wikipedia.org/wiki/Supercooled> ternary solution (STS) of sulfuric acid, nitric acid and water.[4] <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> - Type Ic clouds consist of metastable <http://en.wikipedia.org/wiki/Metastability> water-rich nitric acid in a solid phase.[6] <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-6> - Type II clouds, which are very rarely observed in the Arctic, consist of water ice <http://en.wikipedia.org/wiki/Ice> only.[4] <http://en.wikipedia.org/wiki/Polar_stratospheric_cloud#cite_note-wegener-4> (My highlights) 5) Also, the Harvard website "Equable Climate Dynamics-Polar Stratospheric Clouds <http://www.seas.harvard.edu/climate/eli/research/equable/psc.html>*" *offers a well written oversight of PSC trapping polar heat and the reference section has a number of citations worth reading. 6) And again, we should pay close attention to the paper I originally sited for a view of the PSC dynamics within an ancient "greenhouse" world. Please pay close attention to the 'Discussion' section. Polar Stratospheric Clouds: A high latitude warning mechanism in an ancient greenhouse world: Sloan and Pollard <ftp://ftp.tudelft.nl/pub/TUDelft/irctr-rse/Mieke/Papers/SloanPollard98-PSCforHighLatPTMwarmArctic.pdf> In brief summation, an *intentional* increase in stratospheric sulfuric acid, per SAI, *will* trigger a corresponding increase in the most common PSC type of formation (type 1) and thus this action would represent an *intentional* increase in polar temperatures. Thus, such *intentional* actions would *constitute a knowable action** resulting in the intentional acceleration of polar methane hydrate releases* and the existential threat that such releases pose (i.e. Arctic Methane Tipping Point <https://robertscribbler.wordpress.com/tag/esas/>). Thus, the *intentional* injection of sulfuric acid into the atmosphere represents an real and significant threat to climate stability, as we know it, and will further accelerate the current trend towards an equitable (unstable) climate....*intentionally*. Oliver, thank you for your question and I hope my response offers a reasonable degree of information for you to decide for yourself if SAI is or is not a threat to polar (and global) climate stability as opposed to the current hyperbolicly positive rhetoric concerning the efficaciousness of the SAI concept. Best regards, Michael On Wednesday, February 4, 2015 at 7:53:31 AM UTC-8, olivermorton wrote: > What's the proposed SAI mechanism enhancing PSC? > > On 4 February 2015 at 01:48, Michael Hayes <[email protected] > <javascript:>> wrote: > >> Hi Folks, >> >> This level of discussion on SAI seems to be premature. We have yet to see >> any...any...models concerning the highly predictable increase in Polar >> Stratospheric Cloud (PSC) production which will be caused by SAI. This is >> not a trivial precondition to further discussion. As, the triggering of an >> Arctic Methane Tipping Point, through increasing PSC production, would make >> SAI simply a dysfunctional option. >> >> Please read the following paper concerning the vital need >> to....not...increase PSCs through SAI. >> >> Polar Stratospheric Clouds: A high latitude warning mechanism in an >> ancient greenhouse world. >> <ftp://ftp.tudelft.nl/pub/TUDelft/irctr-rse/Mieke/Papers/SloanPollard98-PSCforHighLatPTMwarmArctic.pdf> >> >> >> Best, >> >> Michael >> >> On Friday, January 30, 2015 at 12:54:21 AM UTC-8, Andy Parker wrote: >>> >>> Hey folks, the Washington Post just published an op ed on the messy >>> politics of solar geoengineering, written by David Keith and me: >>> http://www.washingtonpost.com/opinions/whats-the-right- >>> temperature-for-the-earth/2015/01/29/b2dda53a-7c05-11e4- >>> 84d4-7c896b90abdc_story.html >>> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "geoengineering" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/geoengineering/LJWQD4s2w_U/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> Visit this group at http://groups.google.com/group/geoengineering. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > O=C=O > > Oliver Morton > Briefings Editor > The Economist > > +44 20 7830 7041 > > O=C=O > > *This e-mail may contain confidential material. If you are not an intended > recipient, please notify the sender and delete all copies. It may also > contain personal views which are not the views of The Economist Group. We > may monitor e-mail to and from our network.* > > *Sent by a member of The Economist Group. The Group's parent company is > The Economist Newspaper Limited, registered in England with company number > 236383 and registered office at 25 St James's Street, London, SW1A 1HG. For > Group company registration details go to http://legal.economistgroup.com > <http://legal.economistgroup.com> * > -- 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.
