Ice clouds in the Martian atmosphere

Abstract

Recent spacecraft observations bring a lot of Martian meteorological data to us and then quantitative study on ice clouds in the Martian atmosphere are now beginning to be challenged by using that observational data.
Distribution of the water ice cloud is useful for an index of large scale atmospheric circulation which can not be observe directly, since the Martian water ice cloud can be treated as an atmospheric passive tracer. The Martian carbon dioxide ice cloud over the polar night region, which has not been observed directly by previous instruments, is observed directly by the Mars Orbiter Laser Altimeter carried on the Mars Global Surveyor. It is also important for study on early Mars climate, since the carbon dioxide ice cloud may contribute to warm and moist climate in early Mars owing to its scattering property of infrared radiation. Investigation of formation processes of the carbon dioxide ice cloud and its radiative properties would find a clue to understanding of present and early Mars climate.