An infrared radiative scheme for the numerical models of weather and climate

The entire infrared spectrum is divided into four spectral regions, 20-550, 550-800, 800-1200, and 1200-2200 cm^-1, including the H₂O rotation and 6.3-μm bands, the CO₂ 10- and 15-μbands, and the O₃ 9.6- and 14-μm bands. The continuum absorption of H₂O is incorporated in all the spectral regions. The mean diffuse transmittances in each region for homogeneous paths are calculated by a line-by-line method, and they are approximated with a simple exponential function which contains 10 or 12 parameters. The errors in heating rates are less than 0.3 K/d in the troposphere and stratosphere, and less than 0.8 K/d above the stratopause. The errors in radiative fluxes are less than 0.8 W/m² both at the Earth's surface and the top of the atmosphere. The accuracy of this scheme does not degrade when the CO₂ concentration is doubled. -from Authors