What term describes the process when the ground loses heat at night by long-wave radiation?

The process when the ground loses heat at night by long-wave radiation is known as radiation cooling, which is best described by the term radiation fog. During the night, the Earth's surface emits heat in the form of long-wave infrared radiation. As the ground cools, the air directly above it can also cool, and if the temperature of the air drops to its dew point, moisture in the air can condense, forming fog near the surface. This phenomenon highlights the relationship between temperature, humidity, and the cooling effects of radiative heat loss.

The other terms provided refer to different processes: condensation refers to the transformation of vapor to liquid, evaporation is the process of liquid turning into vapor, and transpiration relates to the release of water vapor from plants into the atmosphere. None of these directly relate to the process of the ground losing heat at night through long-wave radiation, making radiation fog the most appropriate term for the described phenomenon.