Outgoing longwave radiation
Encyclopedia
Outgoing Longwave Radiation (OLR) is the energy leaving the earth as infrared radiation at low energy
. OLR is a critical component of the Earth’s radiation budget and represents the total radiation going to space emitted by 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. Thus, the first law of thermodynamics
(energy conservation) is satisfied and 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 below clear sky values. 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 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 earths skin temperature, skin surface emissivity, atmospheric temperature and water vapor profile, and cloud cover.
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
. OLR is a critical component of the Earth’s radiation budget and represents the total radiation going to space emitted by the atmosphere. Earth's radiation balance
Earth's radiation balance
Earth's radiation balance is the equation of the incoming and outgoing thermal radiation.The incoming solar radiation is short wave, therefore the equation below is called the short wave radiation balance Qs:* G = global radiation...
is very closely achieved since the OLR very nearly equals the Shortwave Absorbed Radiation received at high energy from the sun. Thus, the first law of thermodynamics
First law of thermodynamics
The first law of thermodynamics is an expression of the principle of conservation of work.The law states that energy can be transformed, i.e. changed from one form to another, but cannot be created nor destroyed...
(energy conservation) is satisfied and 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 below clear sky values. Greenhouse gases, such as methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
(CH4), nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
(N2O), water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
(H2O) and carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
(CO2), 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 contribute to global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
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 earths skin temperature, skin surface emissivity, atmospheric temperature and water vapor profile, and cloud cover.