Wednesday, July 21, 2010

An excerpt from 'SuperFreakonomics' on defying Mother Nature and killing Hurricanes

An excerpt (copied from here) from 'SuperFreakonomics' on defying Mother Earth Nature and killing Hurricanes.

Since 1900 more than 1.3 million people worldwide have been killed by hurricanes. Usually hurricanes location is predictable, and even their timing is known. Hurricane is a dynamo that comes without an ‘off’ switch. Once it’s begun amassing energy it cannot be shut down, and it’s far too powerful to be blown back out to sea with a big fan. All you can do is run away.

That’s why physicist Nathan wants to dissipate the thermal energy before it has a chance to accumulate. In other words: prevent the water in Hurricane Alley from getting warm enough to form a destructive hurricane in the first place. The anti -hurricane solution he proposes is so simple that a Boy Scout might have dreamt it up (a very clever one, at least).

The trick is to modify the surface temperature of the water. The interesting thing is that the surface layer of warm water is very thin, often less than 100 feet. And right beneath it is a bulk of very cold water. If you’re skin- ‐diving in many of these areas, you can feel the huge difference. The warm surface layer is lighter than the cold water beneath, and therefore stays on the surface. So what we need to do is fix that. It is a tantalizing puzzle, all that cold water, trillions upon trillions of gallons, lying just beneath the warm surface and yet impotent to defuse the potential disaster.

But he has a solution. It is basically an inner tube with a skirt. That is, a large floating ring, anywhere from thirty to three hundred feet across, with a long flexible cylinder affixed to the inside. The ring might be made from old truck tires, filled with foamed concrete and lashed together with steel cable. The cylinder, extending perhaps six hundred feet deep into the ocean, could be fashioned from polyethylene, aka the plastic used in shopping bags. That’s it!.

How does it work?

Imagine one of these skirted inner tubes,a giant, funky, man- ‐made jellyfish,floating in the ocean. As a warm wave splashes over the top, the water level inside the ring rises until it is higher than the surrounding ocean. When you have water elevated above the surface in a tube like that,’ Nathan explains, it’s called hydraulic head. Hydraulic head is a force, created by the energy put into the waves by wind. This force would push the warm surface water down into the long plastic cylinder, ultimately flushing it out at the bottom, far beneath the surface. As long as the waves keep coming,and they always do,the hydraulic head’s force would keep pushing surface water into the cooler depths, which inevitably lowers the ocean’s surface temperature.

-- Steven D. Levitt, SuperFreakonomics (Chapter 4)
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1 comment:

  1. Should have been Mother Nature instead of Mother Earth.

    ReplyDelete

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