Hi John—I certainly agree with you for dealing with storms generally—not sure you could do for a particular storm, which is what the question/suggestion related to.
On 6/13/09 11:33 PM, "John Latham" <john.latha...@manchester.ac.uk> wrote: > Hello All, > > A further possibility is to attempt to emasculate incipient hurricanes by > cooling oceanic surface waters in regions where hurricanes spawn. One way of > doing this would be to seed low-level shallow clouds in appropriate regions so > as to increase their droplet number concentration and thereby their albedo. > Exploratory GCM exploration of this idea yields the highly provisional result > that a cooling of one or two degrees (perhaps more) could possibly be > achieved: which could be significant vis-a-vis hurricane development.. > > Other cooling ideas could prove to be of importance. > > Cheers, John. > > > > > Quoting Mike MacCracken <mmacc...@comcast.net>: > >> > >> > You need to get more creative. Lowell Wood's idea some decades ago was >> > orbiting mirrors in space that would redirect sunlight on to the storm. The >> > problem remains, however, storm energy is huge, and it is not at all clear >> > that such efforts could trigger a change, much less one would want and be >> > able to predict. >> > >> > Mike M >> > >> > >> > On 6/13/09 6:35 PM, "dsw_s" <ds...@yahoo.com> wrote: >> > >>> >> >>> >> Does a hurricane live moment-to-moment, running entirely on the power >>> >> it dissipates? Or does it accumulate energy, and have its ability to >>> >> release energy depend not only on how much it's dissipating but also >>> >> on how much it has accumulated? >>> >> >>> >> If it depends on accumulated energy, an intervention only has to >>> >> affect an amount of power on the order of the difference between power >>> >> in and power out. If an intervention can make even a small difference >>> >> in energy accumulation rate, then having it run for a long time would >>> >> make a larger difference in the amount of energy accumulated. >>> >> >>> >> My latest thought is to warm the top of the hurricane by suspending >>> >> sheets of black plastic in the air. If we could suspend a square >>> >> kilometer of plastic sheet, the sunshine heating it would be less than >>> >> the power the hurricane dissipates by a factor of something like >>> >> 10**7. That's still a lot of effect-multiplier needed: brute-force >>> >> alteration of the whole hurricane is out of the question, as always. >>> >> A good choice of where to heat the air might let us decrease the >>> >> efficiency with which the storm turns the dissipated heat into >>> >> mechanical work. One way to get some multiplier effect might be to >>> >> use a bunch of smaller sheets to nucleate convection cells and turn a >>> >> region of just-barely-stable air into a region of scattered cumulus >>> >> clouds. Maybe the same thing could be done in the area where >>> >> hurricanes form: instead of having convection cells merge into a >>> >> tropical depression, perhaps they could be managed so that there would >>> >> be enough room for air to sink in between the cells. Or we could go >>> >> the opposite way, making tropical depressions form at the very >>> >> beginning of the season or at the fringes of the area of hurricane >>> >> formation, so that they grow only into moderate tropical storms >>> >> instead of strong hurricanes, and then the sea surface would be cooler >>> >> when hurricanes pass over it. >>> >> >>> >> Replacing a few powerful hurricanes with a larger number of weak >>> >> tropical storms could be a part of overall geoengineering: the smaller >>> >> storms might mix less heat down into the ocean, so that less heat is >>> >> transported to the poles. >>> >> >>> >> On Jun 12, 8:42 am, Mike MacCracken <mmacc...@comcast.net> wrote: >>>> >>> Dear Denis‹You really need to do some order of magnitude estimating: >>>> >>> >>>> >>> Based on the earlier email on the energy involved in and dissipated by >>>> >>> hurricanes, the heat release of a hurricane (on average‹big ones are >>>> higher >>>> >>> by a good bit) is on order of 5.2 * 10**19 Joules per day. Convert that to >>>> >>> calories, assume you want to dissipate 10% of the energy to slow the >>>> storm >>>> >>> down a bit (and this would really mean increasing the natural >>>> dissipation >>>> >>> rate by a factor of 40‹which is lot given that the drag of the surface >>>> >>> ocean is now the major sink of drag energy‹that this factor is so large >>>> >>> should give you real pause). But any way, to deposit the energy you are >>>> >>> talking about as heat in the ocean, your drag devices would have to >>>> >>> warm the >>>> >>> upper 10 meters of the ocean over an area having a radius of 300 km by >>>> >>> roughly 0.3 C‹that is a very great amount (just think how much effort the >>>> >>> Sun takes over the seasonal cycle to warm a bit thicker layer by >>>> somewhat >>>> >>> more). We are talking about huge amounts of energy‹so, on this >>>> argument, I >>>> >>> am on the side of David saying ³nonsensical.² >>>> >>> >>>> >>> Your arguments on CO2 lifetimes, etc. are being addressed by others. >>>> >>> >>>> >>> Mike >>>> >>> >>>> >>> On 6/12/09 3:24 AM, "Bonnelle Denis" <dbonne...@ra.ccomptes.fr> wrote: >>>> >>> >>>>> >>>> About this "beyond nonsensical" idea: >>>> >>> >>>>> >>>> I was just commenting a post which dealt with angular momentum and >>>>> which >>>>> >>>> proposed to use kite devices. About this point, I only added the >>>>> adjective >>>>> >>>> "strong". About ships, their being submitted to storm winds isn't, >>>>> indeed, >>>>> >>>> necessary for my idea: submarines could do the job as well. And they >>>>> could >>>>> >>>> more easily move between inside the hurricane's eye - where the >>>>> surface >>>>> >>>> winds >>>>> >>>> are weaker - and outside the whole hurricane - where the crew could >>>>> safely >>>>> >>>> join the rest of the world. Reversed propellers and other >>>>> hydrodynamic >>>>> >>>> brakes, >>>>> >>>> in order to exchange angular momentum, could be fitted to >>>>> >>>> submarines as well >>>>> >>>> as to ships. >>>> >>> >>>>> >>>> Their "strength" and the kites' one is a matter of design, but mainly of >>>>> >>>> size >>>>> >>>> and finally of materials quantities. I do not pretend that I have >>>>> done the >>>>> >>>> least beginning of an economic appraisal, but if anyone was willing >>>>> to, it >>>>> >>>> would be a good thing. >>>> >>> >>>>> >>>> Best, >>>> >>> >>>>> >>>> Denis. >>>> >>> >>>>> >>>> De : David Schnare [mailto:dwschn...@gmail.com] >>>>> >>>> Envoyé : jeudi 11 juin 2009 13:09 >>>>> >>>> À : Bonnelle Denis >>>>> >>>> Cc : ds...@yahoo.com; geoengineering; lmich...@vortexengine.ca >>>>> >>>> Objet : Re: [geo] Re: Just in Time for Hurricane Season >>>> >>> >>>>> >>>> For those of us who have been on a ship, on the ocean and near a >>>>> >>>> hurricane, >>>>> >>>> much less under it, the idea of having any ship, much less many of >>>>> them, >>>>> >>>> flying kites and reversing engines in some kind of large circle is >>>>> beyond >>>>> >>>> nonsensical. It's sort of like having the government control GM - >>>>> might >>>>> >>>> sound >>>>> >>>> like a good idea, but really! >>>> >>> >>>>> >>>> d >>>> >>> >>>>> >>>> On Thu, Jun 11, 2009 at 5:59 AM, Bonnelle Denis >>>>> <dbonne...@ra.ccomptes.fr> >>>>> >>>> wrote: >>>> >>> >>>>> >>>> This analysis is interesting, but I'd split the first sentence in >>>>> three >>>>> >>>> parts: >>>>> >>>> "To have harmful wind speeds, a hurricane needs to have a large >>>>> >>>> underpressure >>>>> >>>> air column in its middle, and this underpressure has to be >>>>> >>>> protected by the >>>>> >>>> centrifugal force, which results from a lot of angular momentum". >>>> >>> >>>>> >>>> However, when these ideas are being translated to figures (numbers), an >>>>> >>>> important parameter comes in : the radius. The centrifugal force >>>>> effect is >>>>> >>>> negligible at the beginning of the air path (when Coriolis's force >>>>> builds >>>>> >>>> the >>>>> >>>> angular momentum up) and at the end of the same path. It is only in its >>>>> >>>> middle, i.e. at a middle altitude (maybe from 1000 m to 8000 m) that this >>>>> >>>> effect is maximum. >>>> >>> >>>>> >>>> So, if you'd like to use some strong kites to create a drag, a >>>>> >>>> useful device >>>>> >>>> could be to have some boats along a circle in the hurricane's eye, >>>>> being >>>>> >>>> drawn >>>>> >>>> by kites 1000 or 2000 m high, using their propellers as brakes (and even >>>>> >>>> transmitting some mechanichal power to an electrical engine which >>>>> >>>> would act >>>>> >>>> as >>>>> >>>> a power generator). This would transfer the hurricane's angular >>>>> momentum - >>>>> >>>> at >>>>> >>>> the point where this momentum is most implicated in the hurricane's >>>>> >>>> self-stability - to the sea, i.e. it would create an interesting >>>>> angular >>>>> >>>> drag. >>>> >>> >>>>> >>>> Conversely, I am not very much convinced by angular momentum >>>>> >>>> exchanges with >>>>> >>>> the upper layer of the hurricane's air. >>>> >>> >>>>> >>>> Best, >>>> >>> >>>>> >>>> Denis Bonnelle >>>>> >>>> denis.bonne...@normalesup.org >>>> >>> >>>>> >>>> -----Message d'origine----- >>>>> >>>> De : geoengineering@googlegroups.com >>>>> >>>> [mailto:geoengineer...@googlegroups.com] >>>>> >>>> De la part de dsw_s >>>>> >>>> Envoyé : mercredi 10 juin 2009 10:55 >>>>> >>>> À : geoengineering >>>>> >>>> Objet : [geo] Re: Just in Time for Hurricane Season >>>> >>> >>>>> >>>> To have harmful wind speeds, a hurricane needs to have lots of >>>>> angular >>>>> >>>> momentum. If some of the angular momentum could be dispersed to >>>>> >>>> farther from the center of the storm, wind speeds would be lower. If >>>>> >>>> I understand it right, a hurricane has air coming in from the >>>>> >>>> periphery at low altitude, rising in the middle, and dispersing at >>>>> >>>> higher altitude. If the storm is remaining steady or strengthening >>>>> >>>> (in terms of the total angular momentum of its winds), the outgoing >>>>> >>>> air must have less angular momentum than the incoming air by an >>>>> amount >>>>> >>>> at least equal to the angular momentum lost to drag at the surface. >>>>> >>>> Suppose we have something for drag suspended at an altitude where air >>>>> >>>> is moving inward, from balloons at an altitude where air is moving >>>>> >>>> outward. That should transfer angular momentum from the >>>>> inward-moving >>>>> >>>> air to the outward-moving air. >>>> >>> >>>>> >>>> Alternatively, one could fly over the edges of the storm and drop long >>>>> >>>> ropes with a kite on one end and on the other end a weight of >>>>> >>>> approximately the same density of water. The kites would fly >>>>> >>>> themselves for a while before being destroyed, creating drag and >>>>> >>>> decreasing the angular momentum of the air they came in contact with. >>>>> >>>> As the air moved in toward the center of the hurricane, the change in >>>>> >>>> wind speed would be multiplied according to conservation of momentum >>>>> >>>> just as the wind speed itself is. >>>> >>> >>>> >>> >>>> >> > >> > >> > >> > >> > >> > >> > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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