关键词: 地形, 沙尘暴, 大风, 卫星

Abstract: Using the meteorological data of sandstorm, gale and precipitation of the sandstorm center stations and their near stations in northwest China during 1961-1999, the reasons that sandstorms occurred at high frequency in the center stations and at lower frequency in the near stations were analyzed, thinking of the terrain and landcover in these regions and combining the facts revealed by satellites data. The relationship between sandstorm occurrence and terrain was discussed:(1)The surface conditions, the gales and the terrain are the causes of sandstorms occurred at high frequency in these center stations, while the main reason for the near stations is that the gales do not correspond with sand source.(2)The terrain factor has important effect on the occurrence of sandstorms; the thermal instability over dried regions and the air current accelerated and lifted by special terrains have obvious effect on the forming of local sandstorms and triggering of the strong sandstorms.(3)The match of the time in which the gales and the precipitations happen has some influence on the occurrence of sandstorms. Sandstorms occurred frequently while the gale was more and the precipitation was less; and the days of sandstorm occurring decreased distinctly as the rain increased.(4) There is a fine relationship between the sandstorm occurrence and the underlying surface. Gobi deserts are not good for sandstorm occurring, and also the increase of vegetation cover has much effect on restraining the occurrence of sandstorm.

Key words: terrain, sandstorm, gale, satellite