Temporal and Spatial Variations of the Atmospheric Diffuse Light

In order to derive time dependence of the atmospheric diffuse light, which consists of the airglow continuum emission and diffusely scattered radiations of the integrated starlight, the diffuse Galactic light, and the zodiacal light, we have analysed the meridian scan observations of the sky brightness at 5,080 Angstrom and 5,300 Angstrom. Amplitude of the time-variation becomes larger for lower elevation, and maximum amplitude is found to be about 50 S10(V)G2V at elevation 10 deg.. The atmospheric diffuse radiation attains maximum brightness at around midnight, and afterward it decreases slowly with time. The time-variations for the two wavelengths are similar to each other. The observed brightness distribution of the diffuse light along the zenith distance is fitted to an empirical relation of the two parameters. By making the two parameters time-dependent, we describe the spatial and time variations of the atmospheric diffuse light. This enables us to make time dependent correction for the atmospheric diffuse component in the reduction of zodiacal light brightness.