What is the most frequent cause of ground-based temperature inversions?

The phenomenon of ground-based temperature inversions primarily occurs when terrestrial radiation on a clear, relatively still night causes the ground to lose heat efficiently. During the night, especially in calm conditions, the Earth's surface radiates heat away into the atmosphere, leading to a cooler temperature at the ground level. Since the air in contact with the ground cools more rapidly than the air at higher altitudes, this creates a temperature inversion where warmer air sits above the cooler air at the surface.

This condition is conducive to the development of fog, low clouds, and may trap pollutants near the surface, impacting air quality. The significance of terrestrial radiation in this scenario illustrates the crucial role that clear, calm nights play in initiating ground-based inversions, making it the most frequent cause.

Other options describe different meteorological phenomena; for example, the rapid lifting of warm air in mountainous terrains typically leads to cooling at altitude but does not primarily create inversions at ground level as explained above.