Vertical distribution of SO2 in upper cloud layer of Venus and Origin of U.V.-absorption

It is shown that decline of spherical albedo of Venus toward the ultraviolet can be explained by the presence of two absorbing agents: a) SO₂, for which abundance is 10¹¹ cm^?3 at height 68 km and scale height is about 1 km; b) some unknown aerosol absorbent, possibly a 1% FeCl₃ admixture in a sulfuric acid concentrated solution. A mechanism of aerosol formation is proposed.