iCARUS 44, 552--607 (1980) The Astronomical Theory of Climatic Change on Mars

We examine the response of Martian climate to changes in solar energy deposition caused by variations of the Martian orbit and obliquity. We systematically investigate the seasonal cycles of carbon dioxide, water, and dust to provide a complete picture of the climate for various orbital configurations. We find that at low obliquity (15 °) the atmospheric pressure will fall below 1 mbar; dust storms will cease; thick permanent CO2 caps will form; the regolith will release CO2; and H20 polar ice sheets will develop as the permafrost boundaries move poleward. At high obliquity (35 °) the annual average polar temperature will increase by about 10°K, slightly desorbing the polar regolith and causing the atmospheric pressure to increase by not more than 10 to 20 mbar. Summer polar ground temperatures a high as 273°K will occur. Water ice caps will be unstable and may disappear as the equilibrium permafrost boundary moves equatorward. However, at high eccen-tricity, polar ice sheets will be favored at one pole over the other. At high obliquity dust storms may occur during summers in both hemispheres, independent of the eccentricity cycle. Eccentricity and longitude of perihelion are most significant at modest obliquity (25°). At high eccentricity and when the longitude of perihelion is close to the location of solstice hemispherical symmetry in dust-storm generation and in polar ice extent and albedo will occur