Cold-air_pool
Cold-air pool
Accumulation of cold air in a topographic depression
A cold-air pool is an accumulation of cold air in a topographic depression, such as a valley or basin. The cold air is produced by radiative cooling at night along the slopes and sinks down, as it is denser than the surrounding air, settling at the bottom of the depression. The cold dome is trapped by the surrounding higher terrain until a change of air mass or daytime heating breaks the temperature inversion. Since the cold-air pool can persist for long periods, it leads to poor air quality and fog.[1]