Collaborators: Mike Wolff, Todd Clancy

We have developed a 3-D Monte Carlo radiation transfer code to aid in the analysis of several currently available datasets from the Mars Pathfinder, Mars Global Surveyor, and Hubble Space Telescope. In contrast to the traditional plane-parallel radiation transfer model, this code calculates the radiation transfer of the planet as a whole, and therefore accurately accounts for limb effects (where plane-parallel models fail). The surface and atmospheric properties can be specified in a 3-D grid, allowing surface features and clouds to be included. Any number of opacity sources may be specified for the atmosphere. The Monte Carlo radiation transfer algorithms calculate complicated dust scattering functions with the same ease as isotropic scattering. Thus, we can study Martian atmospheric dust properties without requiring approximations for the scattering functions. For surface scattering, we currently use the Minneart law or Lambert law of scattering. The incident sun angle and the observer's viewing angle can be arbitrarily specified. The code allows viewing of the planet from several vantage points: the surface (as from the Pathfinder), low-altitude orbit (Mars Global Surveyer), and from the earth (Hubble Space Telescope). Examples are shown below.

Hubble Space Telescope (HST) Model Images

Pathfinder Model Images

Mars Global Surveyor Model Images

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