Aerosols: A limitation on the determination of ozone from BUV observations

Summary Recent satellite experiments have measured the radiance of the earth at ultraviolet wavelengths and the data thus obtained has been used to determine atmospheric ozone concentrations. It is pointed out in this paper that in the presence of significant concentrations of aerosols at high altitudes, it is not possible from observations of backscattered ultraviolet radiation to separate the effects of aerosols from those attributable to ozone.The earth's daytime horizon was scanned on several occasions between 1963 and 1967 from an altitude of 80 km. For at least one of the flights analyzed we interpret the data to indicate the existence of an aerosol layer at 50 km. This observation, in combination with related observations of other experimenters, implies a limitation on the ability of the backscattered ultraviolet technique to determine ozone concentrations, particularly at altitudes in the region between 35 and 50 km. This limitation may be overcome by altering the viewing geometry and making observations of the earth's horizon. Data thus obtained may be used to deduce the concentrations of both ozone and aerosols.