temperature inversion, condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude. When temperature inversion occurs, cold air underlies warmer air at higher altitudes.
Thereof, how does an inversion happen?
Temperature inversion, a reversal of the normal behaviour of temperature in the troposphere (the region of the atmosphere nearest the Earth's surface), in which a layer of cool air at the surface is overlain by a layer of warmer air. (Under normal conditions air temperature usually decreases with height.)
What is a surface inversion?
Surface temperature inversions occur when air temperature increases with height from the ground surface, which is the opposite of what normally happens (i.e. the temperature profile is 'inverted'). This results in a layer of cool, still air being trapped below warmer air.