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]>; <[email protected]> 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]>; <[email protected]> >> 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: <[email protected]> >>> 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 <[email protected]> >>>> 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 [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 -~----------~----~----~----~------~----~------~--~---
