What type of fog forms in low lying areas due to terrestrial radiation on clear nights?

Radiation fog forms in low-lying areas primarily due to cooling of the ground after sunset, which occurs during clear nights. As the ground loses heat through terrestrial radiation, it cools rapidly, chilling the air directly above it. When the air temperature drops to its dew point, moisture in the air condenses into tiny water droplets, creating fog. This phenomenon typically occurs in valleys and depressions where cool air is trapped, leading to the formation of a dense layer of fog.

Advection fog, on the other hand, is created when warm, moist air moves over cooler surfaces, resulting in condensation. Upslope fog forms when moist air is forced up a slope, cooling as it rises. Steam fog, also known as evaporation fog, happens when cold air meets warm water, causing water vapor to condense into fog. Understanding these different types of fog is essential for safe operations in aviation, as they can significantly reduce visibility.