The word "longwave" refers to a type of electromagnetic wave that has a longer wavelength compared to other waves. It is commonly used to describe radio waves that have a lower frequency and can travel long distances. Full definition
Calculation of solar irradiance i.e. shortwave radiation flux and the atmosphere's heat radiation i.e. longwave radiation flux is important. (en.ilmatieteenlaitos.fi)
Anthropogenic global warming is caused by an increase in the amount of downward longwave infrared radiation coming from greenhouse gases in the atmosphere. (skepticalscience.com)
Interestingly, the near - global observations show a greater drop in outgoing longwave radiation at the CO2 wavelengths around 700 cm - 1 compared to the change over tropical regions. (skepticalscience.com)