AIRS Maps In Motion
Outgoing Longwave Radiation
This map shows AIRS observations of outgoing longwave radiation (OLR). OLR is the energy leaving the earth as infrared radiation at low energy. OLR is an indicator of both how warm the earth's surface is and how clear the atmosphere is overhead. Low values of OLR are typically due to clouds in the atmosphere.
Earth's radiation balance is very closely achieved since the OLR very nearly equals the Shortwave Absorbed Radiation received at high energy from the sun. The OLR is affected by clouds and dust in the atmosphere, which tend to reduce it below clear sky values.
Greenhouse gases absorb certain wavelengths of OLR adding heat to the atmosphere, which in turn causes the atmosphere to emit more radiation. Some of this radiation is directed back towards the Earth, increasing the average temperature of the Earth's surface. Therefore, an increase in the concentration of a greenhouse gas would, in theory, contribute to global warming by increasing the amount of radiation that is absorbed and emitted by these atmospheric constituents.
Outgoing Longwave Radiation (W/m)
