Dear Mark: As I have noted before, you really need to do some order of magnitude estimates and not just what you feel might be needed.
Let's take your 2000 tons of Lair dispersed over 3 days over about the area, let's assume, of a good size of a city. The heat of vaporization (so heat it would take up to vaporize the Lair) is roughly 200 Joules per gram (something you can find in physics references). Each ton is 10**6 grams, and each Joule is about 0.24 calories. Add maybe 24 calories/gram to raise the temperature from the condensation point to a reasonable temperature, and one has maybe 70 calories per gram of total heat uptake. Multiply this out (so 2000 tons times 70 calories per gram times 10**6 grams per ton) and one gets something like 1.5 times 10**11 calories. I switched to calories so I could make a comparison to a nuclear weapons explosive power as we have had such events and had energy (heat rather than cooling) added to the atmosphere and have a sense of the impact. So a megaton is 10**15 calories, a kiloton is 10**12 calories, and Hiroshima and Nagasaki blasts were of order 10**13 calories. If this is all right, the amount of energy you are talking about, even if done all at once, is about a hundredth the size of the Hiroshima or Nagasaki events. You are proposing this energy transfer would be spread over 3 days, so if the nuclear bomb clouds took 5 minutes to dissipate, then divide by another 1000 or so (take a smaller number here if you want). However, during the three days the air is moving and this will greatly spread out your proposed influence. I just do not understand how this would have any significant effect. As another example, let's take a guess at the amount of energy that a tornado-generating convective storm processes. Assume a storm that covers only 5 by 5 kilometers and generates 2.5 cm (1 inch) of rain per hour (both very likely on the low side). So 2.5 cm times 25 square kilometers times 600 cal/g heat from condensation times 10**10 cm**2/km**2 and we get roughly 4 times 10**13 calories--so Hiroshima or Nagasaki size, and injecting the 2000 tons would be 1% of that, and that is sort of the very highest possible ratio--most of these storms are much, much bigger. Again, I don't see how this might work. It would be good for you to work through on this and other order of magnitude analyses, and for someone else to check this all, but if this is anywhere near right, completely aside from the energy it would take to create and insert the Lair, I just don't see how it would have any effect on a large scale or on the tornado scale. Until you can provide really quantitative examples, I don't think advocating Lair is advancing the discussion. Mike MacCracken On 6/5/11 11:54 AM, "m2redmond" <m2des...@cablespeed.com> wrote: > John and Mike- > Thank you for taking the time to consider how Lair might be applied to > increase global albedo or to possibly mitigate storm severity, as well > as other potential applications such as "frosting" permafrost to make > it more reflective or fighting wildfires by releasing liquid nitrogen > (LN2). > > I think because Lair can provide a number of different benefits (which > is a good thing), this has led to some confusion over how specific > strategies might work. I¹ll take the blame on that- I¹ve probably > tried to pack too much information in my previous posts. However, > because Lair has these different possible applications, there is > greater feasibility that one or more of them will provide important > benefits. Performing field tests could answer many of these questions > on short order. > > Please let me try to clarify what I think is needed: > A. The amount of Lair we are considering is very large (100-ton > payloads) and would include multiple heavy-lift aircraft to deliver > enough Lair for the desired result. The specific amount and frequency > would depend on the size and intensity of a particular storm, or in > the case of creating clouds would depend on cloud lifetime. For > example, to mitigate a large storm this might mean 10 aircraft making > two sorties per day or 2,000 tons of Lair for 3 days. For global > albedo, maybe 3 or 4 of these operations might be spaced evenly around > the equator, so that 40 aircraft would deliver 8,000 tons per day on > an ongoing basis (probably an upper bound of what would be needed). > > B. If necessary, certain regions may require a concurrent release of > water vapor and/or CCN¹s (i.e. salt particles) along with Lair, to > form clouds more effectively. > > C. For increasing cloud albedo, Lair could be released at any > altitude- it¹s not limited to creating ice-clouds at high altitudes. > It could also help to form low clouds through condensation and might > increase the droplet density (and therefore reflectiveness) of > existing clouds. > > D. It¹s important to note that the expansion ratio of Lair increases > with altitude, so it expands about 870 times at sea level but 7,500 > times at 50,000 ft. So IF thicker/higher clouds are beneficial, this > could maximize cloud size and lifetime. Despite some opinions that > contrails/cirrus may cause warming, I believe that assumption needs to > be challenged with respect to much thicker and more reflective clouds > at the same altitude (also with respect to 9/11 data which indicated > contrails may actually provide cooling). This could be easily > investigated as part of field-tests. > > E. It¹s also hoped that Lair can leverage existing natural processes, > so that it becomes a catalyst for a much larger natural effect. For > example, the mechanism of deposition causes a chain-reaction when > saturated air is exposed to ice particles (this is how contrails > grow). When Lair cools water vapor to below -40 deg F/C, this should > form large amounts of ice nuclei, and deposition should then cause a > much larger cloud of ice particles to form, the size of which will be > dependent on resident humidity (higher humidity equals larger > effect). A "bounding" example would be to consider releasing Lair at > 28,000 ft (8.5 km), where it would fall and expand into cold air, > cooling a region down to 25,000 ft (7.6 km) where the temperature is > normally -30 deg F (-34 deg C). So if Lair (-319 deg F/-195 deg C) > would cool this region by just 10 degrees, this would create ice > nuclei that should initiate deposition, to form clouds over a larger > region. > > F. Energy calculations for increasing cloud albedo are in work by > Kevin Layton. The challenge here is considering the effects of Lair > for different atmospheric conditions (i.e. different energy states). > However, because the effect of Lair depends on so many variables > (pressure, temperature, humidity, Lair amount, Lair expansion ratio, > resulting deposition, latitude etc.) it might require a computer > analysis to better-determine where it will and will not work. > Ultimately, I believe that field testing will be needed on Lair to > determine where it¹s most effective. > > G. In addition to cloud albedo, Lair might be used to help limit the > severity of future storms. Since severe storms are commonly energized > by the upward flow of water vapor, mixing large amounts of Lair into > these regions should enable the cold air from Lair cause enough > cooling and downward pressure to REDUCE this upward flow by some > amount (this would require field tests and multiple payloads). IF it > works, this could be used to help limit the size and height of storm > systems to reduce hail and flooding, to help minimize the formation of > tornados, and at a larger scale to reduce the severity of hurricanes. > Lastly, by replacing Lair with LN2, the same planes and tank systems > could be used to help fight wildfires that would otherwise burn out of > control. > > Hopefully this helps to answer some questions related to potential > feasibility. Would it help if I created a Wikipedia page that goes > into these details? Or would a White Paper be more appropriate? > > Thanks- > Mark -- 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 geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
