You are right, of course, Mike! Cheers, John.
Quoting Mike MacCracken <[email protected]>: > 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" <[email protected]> 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 <[email protected]>: >> >>> > >>> > 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" <[email protected]> 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 <[email protected]> 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" >>>>> <[email protected]> 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:[email protected]] >>>>>> >>>> Envoyé : jeudi 11 juin 2009 13:09 >>>>>> >>>> À : Bonnelle Denis >>>>>> >>>> Cc : [email protected]; geoengineering; [email protected] >>>>>> >>>> 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 >>>>>> <[email protected]> >>>>>> >>>> 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 >>>>>> >>>> [email protected] >>>>> >>> >>>>>> >>>> -----Message d'origine----- >>>>>> >>>> De : [email protected] >>>>>> >>>> [mailto:[email protected]] >>>>>> >>>> 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. >>>>> >>> >>>>> >>> >>>>> >> > >>> > >>> > >>> > >>> > >> > >>> > >> >> >> >> > > > > > -- John Latham [email protected] & [email protected] Tel. 303-444-2429 (H) & 303-497-8182 (W) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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