What happens to latent heat in the atmosphere during evaporation to what occurs during condensation?

Answer 1

During evaporation, heat energy must by supplied by the atmosphere, the sun, or some other source to cause liquid water to become vapor at the same temperature. This is because energy is needed to overcome the attractive forces between the water molecules. This is similar to the energy that must be supplied to launch a satellite into orbit, as it must overcome the attractive force of gravity.

For this reason, evaporation has a cooling effect, whether it's associated with perspiration on your skin or the evaporation of rain falling through drier air.

When condensation takes place, the reverse occurs: the energy that was supplied to separate the molecules is released again as the molecules accelerate toward each other, collide, and stick, just as a satellite falling back to earth converts potential energy into kinetic energy and ultimately into heat.

The net result of condensation in the atmosphere (i.e., cloud formation) is thus to warm the air. If a cloud forms and then re-evaporates, there is no net heating of the atmospheric, but if a cloud forms and then rain falls out, reaching the surface without re-evaporating, then the atmosphere is warmed in proportion to the amount of rain that fell. It is the release of latent heat that helps drive the intense updrafts in thunderstorms and that provides the energy for hurricanes.

In the big scheme of things, the atmosphere is driven in part by the conversion of sunlight to latent heat at the ocean surface, especially in tropical latitudes, followed by the release of that latent heat in rain clouds, often at locations quite distant from the original source.