Outgoing longwave radiation

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2003-2010 Annual mean OLR
Not to be confused with E-rays.

Outgoing Longwave Radiation (OLR) is the energy radiating from the Earth as infrared radiation at low energy to Space.

Atmospheric energy radiation[edit]

OLR is a critical component of the Earth's energy budget, and represents the total radiation going to space emitted by the atmosphere.[1] Earth's radiation balance is quite closely achieved since the OLR very nearly equals the Shortwave Absorbed Radiation received at high energy from the sun. Thus, the Earth's average temperature is very nearly stable. The OLR is affected by clouds and dust in the atmosphere, which tend to reduce it to below clear sky values.

Role in greenhouse effect[edit]

Greenhouse gases, such as methane (CH4), nitrous oxide (N2O), water vapor (H2O) and carbon dioxide (CO2), absorb certain wavelengths of OLR adding heat to the atmosphere, which in turn causes the respective absorbing layer of 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 contribute to global warming by increasing the amount of radiation that is absorbed and emitted by these atmospheric constituents.

The OLR is dependent on the temperature of the radiating body. It is affected by the Earth's skin temperature, skin surface emissivity, atmospheric temperature, water vapor profile, and cloud cover.[1]

See also[edit]


  1. ^ a b Susskind, Joel; Molnar, Gyula; Iredell, Lena. "Contributions to Climate Research Using the AIRS Science Team Version-5 Products". NASA. Goddard Space Flight Center. Retrieved 14 September 2011. 

External links[edit]