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. >> >> > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
