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The vibrational and rotational excited states of greenhouse gases that emit thermal infrared radiation are in LTE up to about 60 km. [7] Radiative transfer calculations show negligible change (0.2%) due to absorption and emission above about 50 km. Schwarzschild's equation therefore is appropriate for most problems involving thermal infrared in ...
Earth constantly absorbs energy from sunlight and emits thermal radiation as infrared light. In the long run, Earth radiates the same amount of energy per second as it absorbs, because the amount of thermal radiation emitted depends upon temperature: If Earth absorbs more energy per second than it radiates, Earth heats up and the thermal radiation will increase, until balance is restored; if ...
Radiative forcing is defined in the IPCC Sixth Assessment Report as follows: "The change in the net, downward minus upward, radiative flux (expressed in W/m 2) due to a change in an external driver of climate change, such as a change in the concentration of carbon dioxide (CO 2), the concentration of volcanic aerosols or the output of the Sun." [3]: 2245
It has since become a common introductory "textbook model" of the radiative heat transfer physics underlying Earth's energy balance and the greenhouse effect. [ 3 ] [ 4 ] [ 5 ] The planet is idealized by the model as being functionally "layered" with regard to a sequence of simplified energy flows, but dimensionless (i.e. a zero-dimensional ...
The heat transfer coefficient has SI units in watts per square meter per kelvin (W/(m 2 K)). The overall heat transfer rate for combined modes is usually expressed in terms of an overall conductance or heat transfer coefficient, U. In that case, the heat transfer rate is: ˙ = where (in SI units):
Radiation heat flow occurs in the direction from the surface to the atmosphere and space, [6] as is to be expected given that the surface is warmer than the atmosphere and space. While greenhouse gases emit thermal radiation downward to the surface, this is part of the normal process of radiation heat transfer. [77]
Climate sensitivity is a key measure in climate science and describes how much Earth's surface will warm for a doubling in the atmospheric carbon dioxide (CO 2) concentration. [1] [2] Its formal definition is: "The change in the surface temperature in response to a change in the atmospheric carbon dioxide (CO 2) concentration or other radiative ...
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes.