Abstract: Sand dust storm is a special natural disaster that frequently occurrs in deserts and their surrounding areas. With the data published on Surface Meteorological Monthly Bulletin and Surface Chart during 1971～1996, the temporal spatial distribution and annual variation of sand dust storms are analyzed on the basis of the case study of atmospheric process. Furthermore, the tracks and source areas of sand dust storms are determined assisted with GIS. The results show: Except parts of Qinghai Province, Inner Mongolia and Beijing, the sand dust storms decrease greatly both in time and space in recent decades in China. Sand dust storms occur most frequently in spring, especially in April. According to their source areas, the sand dust storms are classified into two types, i.e. the inner source and outer source sand dust storms. Most of the outer source sand dust storms move along the north and west tracks. For the north track outer source sand dust storms, they always intrude into China across the Sino Mongolian boundary from Hami, a city in the eastern part of Xinjiang, to Xilin Gol, a county in Inner Mongolia, while the west track ones intrude into China both from southern Xinjiang and northern Xinjiang. The source areas of inner source sand dust storms are the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in northern Xinjiang, Hexi Corridor in the west of Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai.

Key words: Sand dust storm, temporal spatial distribution, tracks, source areas