What type of fog is primarily formed by the cooling of the air near the ground?

Radiation fog is primarily formed by the cooling of the air near the ground. This type of fog occurs on clear nights when the terrestrial radiation causes the temperature of the earth’s surface to drop rapidly, leading to the cooling of the air directly above it. As the ground cools, moisture in the air condenses into tiny water droplets, forming fog. This process is particularly effective when there is little wind, as the stagnant air allows for the temperature to reach the dew point.

In contrast, advection fog forms when warm, moist air moves over a cooler surface, leading to condensation. Steam fog is created when cool air comes into contact with warm water, allowing moisture to evaporate and then condense. Upslope fog forms when moist air rises up a slope, cools, and condenses. Understanding these different processes helps clarify why radiation fog specifically arises from ground-level cooling.