(SW) is a term used to describe the radiant energy
in the visible
(UV), and near-infrared
(NIR) wavelengths. The wavelength range is not always exactly defined, as there is no standard cut-off for the NIR. Shortwave radiation may be as broadly defined as between 0.1 and 5.0 micrometers
) or as narrow as 0.2 to 3.0 micrometers, as there is little radiation flux (in terms of W/m^2) to the Earth's surface below 0.2 micrometers or above 3.0 micrometers (the photon flux, however, remains significant well to 6.0 micrometers, compared to the shorter wavelength fluxes). UV-A radiation is 0.315 to 0.400 micrometers, UV-B 0.280 to 0.315 micrometers, UV-C 0.100 to .280 micrometers, visible 0.400 to 0.700 micrometers, and NIR 0.700 to ~5.0 micrometers, beyond which the infrared is thermal. However, the definition of thermal infrared may start at wavelengths as short as 1.1 micrometers (longer than which optical instruments have difficulty measuring), or 2.0 to 4.0 micrometers, depending on the method and use of the measurement.
This is compared to longwave radiation.
- Zhang, Y., W. B. Rossow, A. A. Lacis, V. Oinas and M. I. Mischenko (2004). "Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data." Journal of Geophysical Research-Atmospheres 109(D19105).