If heat rises...
 

...why are mountaintops so cold?

Warm air usually rises only because it has lower density than the cooler air surrounding it. At high altitudes, where air pressure is low, warm air from low altitudes is more dense, and will not penetrate this altitude.

Air at low altitudes is warmer in the first place because it is warmed by heat radiation from the earth.

Ah, thanks. *bows before jeebus*;)

quote:

"Air at low altitudes is warmer in the first place because it is warmed by heat radiation from the earth."

Air at lower altitudes is warmer because the surface of the earth is warmed from the sun's radiant heat. As global/local winds convect, the "water vapor/gas mix" (we call air) absorbs heat from the surface of the earth in an attempt to reach equilibrium. Law of thermodynamics, heat flows from zones of higher energy to those of lower energy.

-SF

It's all so very interesting.

The albedo (ratio of reflected/absorbed solar radiation) of the surface of the earth also has a lot to do with the surface temperature. The solar radiation will heat the air both on its way down and on its way back into the atmosphere.

Also, to a lesser extent, there are fewer molecules in the air at higher altitudes, therefore, there are fewer molecules to bump together to raise the temperature of the air.