|radiational cooling (rā'dē-ā'shə-nəl) Pronunciation Key
The cooling of the Earth's surface and the air near the surface, occurring chiefly at night. It is caused by the emission of infrared radiation from the Earth's surface and from the tops of clouds and the atmosphere. Because infrared radiation is absorbed by water vapor, cloudless nights usually allow for greater radiational cooling than overcast nights. Radiational cooling occurs in all regions of the Earth and is important in maintaining the Earth's energy balance.