Radiation Flux - This is defined as the way heat from the sun is absorbed, scattered, returned, or deposited around the earth and can be expressed as some radiation arrival rate per the unit of area of the surface. The radiation flux can be the total amount of radiation that the earth collects, emits, and disperses.
[Oil and Gas Journal ; v.91; pages 45-48; 1993.]
[Nature; v.343; pages 251-254; 1990.] 
Atmospheric Chemistry Glossary