What is the cause of a surface temperature inversion?

A surface temperature inversion occurs when warmer air is situated above cooler air near the ground. This phenomenon is principally caused by heavy radiational cooling at night or when warm air moves over a colder surface.

During the night, the Earth's surface cools rapidly due to radiative heat loss, leading to lower temperatures at ground level. If there is still air above this cooled layer, it remains warmer, creating a temperature inversion. Similarly, when warm air flows over a colder surface, the cooler surface can also chill the air directly in contact with it, leading to a stable layer of warm air above a cooler layer.

This dynamic results in an inversion layer that can trap pollutants and lead to fog or low clouds because the cooler air is unable to rise. Understanding this process is crucial for predicting weather patterns and interpreting atmospheric stability, as inversions can significantly impact aviation operations and air quality.