Methane abundance in the atmosphere of Uranus

Abstract

Modeling of the geometric albedo of Uranus in and near prominent methane absorption bands between 0.5 and 0.9 μm indicates that the visible atmosphere probably consists of a thin aerosol haze layer ( τ scat ≅ 0.3−0.5; ω H ≅ 0.95) above an optically thick, semi-infinite Rayleigh scattering atmosphere. A significant depletion of methane gas above the haze layer is indicated. The mixing ratio of methane in the lower atmosphere is consistent with a value of CH 4/H 2 ≅ 3 × 10 −3, comparable to those derived for Jupiter and Saturn.