Sand-dust storm is a weather event mainly occurred in the arid and semi-arid regions of the world,which is caused by the sand and dust blown into the atmosphere by strong wind.After its occurrence,the atmosphere becomes very dusty and the sight distance in the horizontal direction is less than 1000m.Sand-dust storm is also a natural event that can cause serious disaster and soil erosion.Consequently,sand-dust storm can be a indicator of the degree of desertification.
The occurrence of sand-dust storm is mainly controlled by atmosphere circle,weather condition,and characteristics of land cover.However,after its occurrence,human being can do nothing to it.To reduce its occurrence frequency and the possible caused disasters,the only practicable way is to improve the condition of land cover.Therefore,researches focus on the relationship between land cover and sand-dust storm can not only reveal the occurrence mechanism of sand storm but also provide the theoretical basis to control it.Besides,these researches can also provide theoretical basis for the actions to improve the eco-environment in Northwest China.