The Uranian Geometric Albedo: An Analysis of Atmospheric Scatterers in the Near-Infrared

Narrowband images of Uranus in the near-infrared from Apache Point Observatory were employed to derive the globally averaged properties of scatterers in the atmosphere in the post-Voyager epoch. In order to best probe different levels of the stratosphere and upper troposphere we measured and modeled the planetary geometric albedo using seven filters ranging from 1.28 to 2.36 μm. Since 1986 there has been a 20-fold increase in the stratospheric haze-column density, while the tropospheric cloud characteristics have remained largely the same. Our results suggest an upper limit on the optical thickness of the lower H₂S cloud of 15 at 1.58 μm.