Question

The ground temperature is 12°C. If the temperature at 300 m is 10°C, is the atmosphere stable, neutral, or unstable? If the ground temperature rises during the day to 15°C, but the temperature at 300 m remains at 10°C, what happens to the atmospheric stability?

Answer 1

Atmospheric stability is a measure of the atmosphere's tendency to encourage vertical motion, and vertical motion is directly correlated to different types of weather systems and their severity. In unstable conditions, a lifted thing, such as a parcel of air will be warmer than the surrounding air at altitude. Because it is warmer, it is less dense and is prone to further ascent.

So in first case atmosphere is stable as is follow normal lapse rate of temperature (6.5°C per kilo meter).

In second case atmosphere remain neutral because temperature does not increases as temperature of ground level increases.