INFLUENCE OF PLANETARY-SCALE TOPOGRAPHY ON THE DIURNAL THERMAL TIDE DURING THE 1971 MARTIAN DUST STORM.

Abstract

Data obtained with the Mariner 9 infrared spectroscopy experiment during the Martian dust storm of 1971 to 1972 are examined for evidence of topographic influence on the atmospheric thermal structure. Temperature perturbations which are well correlated with the planetary-scale topography are found superposed on the large-amplitude diurnal thermal tide previously reported. Applications of tidal theory to the data indicate that the observed perturbations result from the kinematic interaction of the westward traveling diurnal wave with the large-scale components of topography. The dominant mode is excited by the wavenumber 2 topography component. Other waves excited include vertically propagating modes which produce little effect in the lower atmosphere, but may represent a source of energy for the upper atmosphere during dust storm conditions.