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A high resolution spectral radiative transfer model of the troposphere for computing downwelling radiance and flux density at the surface in the 5–200 μm region has been developed. The model is fast and accurate and takes into consideration all major and minor constituents active in this region, namely, water vapor, carbon dioxide, ozone, nitrous oxide, and methane. It uses the quasi-random band model of absorption for computing atmospheric transmittances due to various bands. Continuum absorption by water vapor in the 8–14 μm region has also been taken into account.

Production rates of N(2D) metastable atoms in the daytime atmosphere have been calculated for different possible processes, using positive ion composition and reaction rate data, available presently. Emission rates of the 5199 Å doublet of Ni are calculated by separately and jointly considering the deactivation of N(2D) atoms by electrons and molecular oxygen.

Rates of production of O(1D) atoms in the upper atmosphere by photodissociation of O2, dissociative recombination of O2+, NO+ and electron impact excitation of O(3P) have been calculated for low, medium and high levels of solar activity. Variations with solar activity, of neutral and ionic composition, electron and neutral temperatures of the upper atmosphere and solar extreme ultraviolet fluxes incident on it have been taken into consideration.