Can warmer air really hold more water?

Cutlass1287

Cutlass1287

Well-Known Member
...I don't think so. Now, some seem to think that this is pure semantics, but I tend to disagree. See the following links.

http://www.ems.psu.edu/%7Efraser/Bad/BadClouds.html

http://www.atmos.umd.edu/~stevenb/vapor/

If I am interpretting this information correctly, this seems to be true: If air is hotter, it increases the energy of the water molecules in the puddle, so they break free and evaporate-> Now we have more airborne water vapor. If the air cools, they lose energy and condense back into the puddle-> We have less airborne water vapor. Any thoughts on this?
 
Come to Florida and experience just HOW MUCH water warm air can hold. It's like walking through a 90 degree blanket.
 
Warm air can hold more water, but...the use of "hold" and "capacity" are really missleading when in comes to water vapor content. Air does not really hold in the sense of making room for water vapor.

Let's take a look at Saturation Vapor Pressure to see why.
SVP is the pressure that the water vapor molocules would exert if the air were saturated with vapor at a given temperature.

So imagine molocules evaportaing from a water surface. When the air above the water is saturated, the number of molocules escaping from the water surface equals the number returning to the water. As heat (energy) is added to the water, its temperature increases, and the molocules move faster. So in turn the number of molucles escaping also increases. To maintain the balance between the escaping and returning molocules of water vapor, this causes an increase in the number of water molucules in the air above. So at higher temperatures, it takes more water vapor to saturate the air. More vapor molcules exert a greater pressure, so SVP depends on the air temperature.
 
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