NSIDC's website will undergo planned maintenance on Wednesday, January 15, from 10 a.m. to 12 p.m. (U.S. Mountain Time). During this time, the NSIDC.org website and most NSIDC data access may be briefly unavailable.
the difference between the outgoing infrared (longwave) terrestrial radiation of the earth's surface and the downward infrared counter-radiation from the atmosphere.