Spectrophotometrical experiment on the Venera-13 and Venera-14 landers

Spectra of solar radiation in the range 0.45 lambda 1.2 mkm scattered in the deep layers of the Venusian atmosphere were registered by spectrophotometers of Venera-13 and Venera-14 at 6 different angles at all the heights between 62 km and the surface. The water vapor abundance was estimated from the intensity of H2O bands between 0.7 mkm and 1 mkm. Water abundance near the surface is about 10/20 ppm and by the order of magnitude more at a height of about 40 km. The water profile with the maximum of mixing ratio between 40 km and 60 km can be in approximate agreement with all the water measurements provided on board Venera-13 and Venera-14 by three different methods. Ultraviolet intensity at lambda = 0.37 mkm with some filter device was also measured. Ninety percent of the solar radiation in this range is absorbed in the clouds above the level of 58 km.