Profiles of scattered light above the planetary limb from over 100 Viking Orbiter images are used to constrain the temporal and spatial behavior of earosols suspended in the Martian atmosphere. The data cover a wide range of seasons, locations, and viewing geometry, providing information about the aerosol optical properties and vertical distribution. The vertical resolution of the data is about 1.5 km, with an absolute elevation accuracy of 1 to 4 km. Viking Orbiter camera colibration algorithms provided reflectance accuracies to 7% absolute allowing meaningful radiometric analysis. The typical atmospheric column contains one or more discrete, optically thin, ice-like haze layers between 30 and 90 km elevation, depending on season, whose composition is inferred to be water ice. Below the detached hazes there is a continuous haze extending to the surface. The continuous haze is rarely observed above 50 km and is much redder in color than the detached hazes above, implying a composition that has a strong dust component. The aerosol distribution exhibits a strong seasonal control inferred to be driven by the variable solar flux around the orbit of Mars.