- the cooling of the earth's surface and adjacent air, primarily at night, caused by a loss of heat due to surface emission of infrared radiation.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- 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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.