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 -~----------~----~----~----~------~----~------~--~---
