From Glossary of Meteorology


The downward flux of longwave radiation across a given surface, usually taken as the earth's surface.

Counterradiation originates in emission by clouds and greenhouse gases at different heights and temperatures, and is modified by subsequent absorption before reaching the surface in question. The long-term global average of counterradiation reaching the earth's surface is about 330 W m-2, making it one of the largest terms in the surface energy balance.