Viking observations of Martian dust storms

Local dust storms, global dust storms and background aerosol in the Martian atmosphere have been recorded by the Viking orbiters and landers. Local dust clouds are most prevalent in certain areas of the southern hemisphere during spring; local storms at the edge of the retreating south polar cap and in the 15 to 25 deg latitude band are discussed. A major global storm characterized by clouds as high as 30 km and mean meridional wind speeds of 10 m/sec has also been studied. The global storms monitored by the Viking mission spread rapidly, with the most intense activity limited to a brief period.