Analysis of the Earth's ultraviolet radiation variability from satellite measurements and model calculations

Abstract More than 7000 spectrograms of nadir ultraviolet radiation measurements at λ = (0.28–0.34) μ m from satellite “Meteor” in 1985–1987 over different regions are systematized according the sets of λ values and solar zenith angles θ. The factors of radiation variability at λ = 0.34 μ m and θ = (15°–30°) are analysed. It is found from 1500 spectrograms that the maximum brightness exceeds the minimum in 6.5 times and the most frequently registered brightness is 2.5 times higher than the minimum. The brightness is calculated according to the atmosphere radiation in the 0 – 74 km height region at λ = 0.34 μ m for the model of ozone absorption with different ozone content, molecular and aerosol scattering, different heights of the underlying surface H and the reflection coefficient K . The most frequently registered brightness corresponds to cloudiness with K = (0.3–0.4) in the presence of aerosols. The minimum levels of measured brightness correspond to calculated levels at H = 0 and K = (0.1–0.2); the maximum brightness is comparable with the model for nonaerosol atmosphere with K = 1.