Dear Alvia, If H2S applied to the stratosphere, would the additional hydrogen impact i) HOx chemistry and therefore ozone loss and ii) increased water vapor which is a greenhouse gas and could lower the threshold for PSC formation?
Oliver On Dec 9, 10:32 am, "Alvia Gaskill" <[EMAIL PROTECTED]> wrote: > 1. I think that at a minimum, the release altitude has to be 65,000 ft and > at most, 90,000 ft as you don't gain much residence time above 90,000 ft. > The aerosol just starts to descend. > > 2. The preferred precursor liquid is H2S, since that reduces the quantity > required by a factor of 2 if SO2 were used. > > 3. The figure of 1Tg/yr would probably be a good starting point as if such a > program were run for several decades, levels on this order would be > approached. Of course, all those other issues about what happens to the gas > after it is released still have to be addressed, but getting it there is job > no. 1 > > 4. The problem of unit mass is the same one faced by the NAS-92 panel when > considering how many shells containing dust would have to be fired. If you > need to get 1 million tons of H2S into the stratosphere per year, then that > works out to 2700 tons per day. If a shell can hold 1000 lbs (which I think > will turn out to be about the limit for any type design), then that would > require 5500 shots per day or 2 million/yr. That means lots of guns as they > will wear out pretty fast. The fuel per ton issue is probably valid, but > the planes already exist and can be repaired as needed. Dispersal is a key > problem with this and with tanks carried by airplanes as the liquid has to > quickly turn into a vapor. If the drops are too large, that may cause much > of it to simply fall rapidly. On the otherhand, if it is released in an > explosion, in the way that artillery shells usually work, then there might > be sufficient dispersal and also conversion to SO2 through oxidation. All > these issues aside, I think the number of shots is the biggest obstacle. > And if you've ever had to work with a bunch of big shots, you know what I'm > talking about. That was a joke. > > ----- Original Message ----- > From: "Roger Angel" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > > Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; > <geoengineering@googlegroups.com> > Sent: Tuesday, December 09, 2008 11:02 AM > Subject: Re: [geo] Re: delivering aerosols > > > Re gun delivery, > > I have a student who working on delivering liquid aerosol precursor such > > as liquid SO2 to ~ 25 km altitude with optimized vertical pointing guns. > > We are looking at the basic physics of acceleration, pressure containment > > etc and the energy budget for various options of combustion, air pressure > > and magnetic force to do the acceleration. The acceleration has to be > > relatively low to keep down the thickness and mass of the steel launch > > vessel, leading to a vertical acceleration path of about 100 m. For > > acceleration by gas pressure, which is about equal to the pressure in the > > liquid, the barrel will be quite lightly built, not like an artillery gun. > > The alternative of magnetic acceleration gives the best energy efficiency > > but will take longer to develop. Any gun method is likely to use much > > less fuel per ton delivered than aircraft delivery, with far less wear and > > tear. > > > Questions to the group - what is the preferred precursor liquid and > > height? Is a million tons a year about the right delivery rate? What unit > > mass would be best? Will it be necessary to disperse the liquid by a > > small explosive charge, like a firework? An optimized gun delivery system > > would be fairly quick to develop, prototype and test, for perhaps a > > hundred million dollars. > > > Roger Angel > > > Alvia Gaskill wrote: > >> Artillery shells cannot hold very much material, requiring an excessive > >> number of shots be fired. If liquid H2S were to be loaded into such a > >> shell, it also might not disperse sufficiently. There are also no guns > >> available for firing the shells. NAS-92 looked at their potential for > >> firing dust containing shells, but the same concerns apply. > > >> Atmospheric nuclear testing was banned in the 1960's and for good reason. > >> Radiation disperses and enters the environment causing mutations, cancer > >> and death. That's why we have the IAEA, the non proliferation treaties > >> and UN sanctions against Iran. There is no safe way to use nuclear > >> weapons. > > >> Volcanic eruptions up to the scale of Pinatubo are relatively benign in > >> their side effects. Tambora and Laki-sized eruptions disrupted the > >> global climate and killed thousands of people. A Yellowstone or Toba > >> eruption would be like a global nuclear war. It would kill almost > >> everyone. Volcanoes also don't release large amounts of radiation. > > >> ----- Original Message ----- > >> From: "Andrew Lockley" <[EMAIL PROTECTED]> > >> To: <[EMAIL PROTECTED]> > >> Cc: <[EMAIL PROTECTED]>; <geoengineering@googlegroups.com> > >> Sent: Monday, December 08, 2008 10:13 AM > >> Subject: [geo] Re: delivering aerosols > > >> Please don't make personal digs just because I suggested an idea that > >> may not work. > > >> Why is a nuclear bomb worse than a volcano anyway? > > >> And what about artillery as a method? > > >> 2008/12/8 Alvia Gaskill <[EMAIL PROTECTED]>: > > >>> The only people seriously considering using nuclear weapons to put lots > >>> of > >>> particulate matter into the stratosphere live in the tribal areas of > >>> Pakistan. Alan Robock showed what happens if India and Pakistan play > >>> nuclear ping pong with their meager arsenals. The particulate matter > >>> carried into the stratosphere absorbs enough solar energy to heat the > >>> stratosphere to the point where reactions that destroy ozone are > >>> maximized. > >>> The net result is that everyone and everything on the surface of the > >>> Earth > >>> is killed by UV radiation. Now you wouldn't want that, would you > >>> Andrew? > >>> Your organization is called Friends of the Earth, isn't it, although the > >>> acronym FOE is a little disturbing. > > >>> I've looked at the delivery system issue (see the group files for some > >>> of > >>> what I've written) and concluded that airplanes and balloons could be > >>> used. > >>> To get precursor gas to circulate globally, it must be released above > >>> 53,000 > >>> ft, the boundary between the tropical tropopause and the stratosphere. > >>> In > >>> fact, due to the fall rates of aerosol, it should be released at above > >>> 65,000 ft to guarantee at least a one-year residence time in order to > >>> make > >>> it practical. The B-52, the KC-135 and other large subsonic aircraft > >>> cannot > >>> fly this high, their ceilings right at around 50,000 ft. To fly as high > >>> as > >>> would be necessary and carry enough payload to make it worthwhile would > >>> require supersonic aircraft. I settled on the F-15c with a ceiling of > >>> around 65,000 and the ability to carry about 8 tons of payload of which > >>> half > >>> could be the gas. > > >>> You are correct about the balloons in that using hydrogen as the lifting > >>> gas > >>> instead of helium doubles the lifting capacity. Using H2S instead of > >>> SO2 > >>> doubles the precursor quantity that can be carried again as well. So > >>> balloons containing hydrogen and H2S within the envelope of the balloon > >>> could deliver the gas to the stratosphere in the quantities required and > >>> to > >>> much higher altitudes as well, up to 120,000 ft. The technology to > >>> inflate > >>> and recover payloads from large football stadium sized stratospheric > >>> balloons exists today and has been used since the 1940's to deliver > >>> payloads > >>> of up to 8000 lbs to 120,000 ft and recover them. > > >>> The real issue about the delivery systems is whether or not the gas will > >>> form the proper sized aerosol using the existing water vapor in the > >>> stratosphere. This will requre field tests to determine its feasibility > >>> as > >>> well as whether gas can be released from tanks quickly enough to > >>> vaporize in > >>> the time that the planes can spend in flight at these altitudes, > >>> probably > >>> about an hour. Balloon residue can be addressed through a collection > >>> program and I doubt the residue would come close to that already > >>> floating in > >>> the middle of the Pacific from land based plastic waste. Alan Robock's > >>> statement in his AMS slides that "billions of weather balloons would be > >>> required" is only accurate if weather balloons were used. High altitude > >>> stratospheric balloons are not weather balloons. > > >>> ----- Original Message ----- > >>> From: "Andrew Lockley" <[EMAIL PROTECTED]> > >>> To: <[EMAIL PROTECTED]> > >>> Cc: <geoengineering@googlegroups.com> > >>> Sent: Monday, December 08, 2008 6:14 AM > >>> Subject: [geo] Re: delivering aerosols > > >>> As they are just converted old bombers you could easily convert a > >>> different bomber to do the job. B52s are an obvious choice as there > >>> are loads lying about and they are very large, reducing the costs. I > >>> think they fly very high. > > >>> A > > >>> 2008/12/8 <[EMAIL PROTECTED]>: > > >>>> These planes cannot reach the sub-stratosphere at all. > >>>> Gregory > > >>>> Has anyone looked at using firefighting planes to deliver aerosol > >>>> particles? > > >>>> -----Original Message----- > >>>> From: Andrew Lockley <[EMAIL PROTECTED]> > >>>> To: geoengineering <geoengineering@googlegroups.com> > >>>> Sent: Sun, 7 Dec 2008 5:46 pm > >>>> Subject: [geo] delivering aerosols > > >>>> Has anyone looked at using firefighting planes to deliver aerosol > >>>> particles? These are designed to spray powder. There are a lot of > >>>> them about in Northern latitudes, and for much of the year they really > >>>> don't do a lot. > > >>>> I've seen several other methods, all of which have disadvantages: > >>>> 1) Space lift - still scifi > >>>> 2) Balloons - could work, but would have to be hydrogen, not helium > >>>> due to the volumes needed. Unless the balloons are programmed to > >>>> deflate and float back down, there will be a lot of 'litter'. To get > >>>> a decent payload, a very large flammable balloon would be needed. > >>>> 3) artillery - possibly useful, but may be a lot more polluting, > >>>> expensive and energy intensive than a plane. > > >>>> ________________________________ > >>>> Listen to 350+ music, sports, & news radio stations – including songs > >>>> for > >>>> the holidays – FREE while you browse. Start Listening Now! --~--~---------~--~----~------------~-------~--~----~ 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 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 -~----------~----~----~----~------~----~------~--~---
