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Old 03-July-2009, 06:52 PM
lomiller1 lomiller1 is offline
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Quote:
Originally Posted by JohnD View Post
But how does it work? Water vapour can be condensed by cooling it, but that requires removal of energy from the system. It will also condense if the pressure falls, but that also occurs only if energy is removed. Condensation neither adds nor subtracts from the system's energy total, but how does it 'release' energy to build tornados, hurricanes or thunderstorms?
I’m not a meteorologist but:

Warm air rises, because it’s less dense then the surrounding air

At higher altitudes atmospheric pressure is less so the air mass expands

This expansion of the air mass causes it’s temperature to drop.

As the temperature decreases the amount of water vapor the air can hold is reduced so it’s forced to condense into particles.

To do this the water vapor must give up heat, this heat acts to offset the cooling caused by the expansion of the air mass.

The overall effect of this adiabatic effect is to carry energy upwards away from the surface and where it drives storms.
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