A general overview of what is known about the Martian atmosphere and its effects on the physiography of the surface is presented. The composition of the atmosphere of Mars is examined and some of the fluctuations of atmospheric constituents are discussed and followed by a review of the major geological features and what they imply about the behavior of the atmosphere. The characteristics of the Martian general circulation, the aeolian wind regime, and the global dust storm are described. Theories about the evolution of Mars' atmosphere and the possibility of climatic variation are examined. Project Viking, the major project of Martian research in the next several years, is briefly described.
1 Now at Department of Atmospheric Sciences, University of Washington, Seattle, Wash. 98195