How can latent heat affect atmospheric stability?

1 Answer
Nov 4, 2015

Latent heat is fundamental in thunderstorm formation.


As air rises in the atmosphere it cools. This is due to the reduced air pressure causing the parcel of rising air to expand.

Air can only hold so much water vapor, based on temperature (warmer air holds more water vapor). So if a rising parcel of air cools it will eventually reach a point where it is holding all the water vapor it can. Any further cooling will cause condensation. This is how clouds form.

During condensation the change of state from gas to liquid releases latent heat. If the air parcel continues to rise it will still cool, but at a slower rate than when condensation was not occurring. So if this parcel of air continues to be lifted and it cools at a slower rate, eventually it will be warming than the surrounding air. This is called the level of free convection and is the point that the air no longer has to be lifted, it will rise on it's own due to the buoyancy of the warm air.

This is what has to occur in order for thunderstorms to form. Without latent heat this process would not occur. Thunderstorms are an extremely good indicator of atmospheric stability.