关键词: 生态演变, 沙尘暴, 规律

Abstract: A comprehensive analysis on sandstorm evolvement and annual ecological variance was conducted in the area where sandstorms occurred frequently in Ningxia by making use of the detailed survey data of the main eight land types, sandstorm and wind regimes in Ningxia in past 10 years, and integrating the Asia circulation index and reanalyzed data of NCEP in 1990—2002. Result shows that the ecological environment in Ningxia was degraded, especially in the drought strip in middle Ningxia. Because of the decreasing of pasture and plough field apparently, the descending of grass quality and capacity of feeding livestock, the deterioration of ecological environment is much more serious; meanwhile under same meteorological circumstance, in recent 10 years, the wind speed before and after sandstorms reduced, which has close correlation with the ecological features of this region. Sandstorms were likely to happen in April, and the occurrence increased in later 1990s. The above means that the deterioration of ecological environment resulted in the descent of sandstorm threshold wind and the obvious increase of occurrence possibility.

Key words: ecological evolvement, sandstorm, occurring law