Topographic and Atmospheric Pressure Mapping of Mars

Introduction: The topography of Mars remained unknown until the first orbiting spacecraft, since early ground-based observations of Mars displayed only variations due to albedo which correspond to changes in surface composition and texture rather than changes in surface altitude. However a technique was being developed in the late 1960s and early 1970s to determine the Martian topography by measuring the spatial variation in the strength of the atmospheric CO2 absorption bands [1, 2, 3] and was later improved for use over limited Martian equatorial regions with the ISM instrument on board the Russian spacecraft Phobos 2 [4]. The observations presented here use near-infrared ground-based observations to produce relatively detailed topographic maps of Mars that correlate well with topographic maps produced by the Mars Orbiting Laser Altimeter (MOLA) on board the Mars Global Surveyor (MGS).