An analysis of the potential impacts of ecological restoration on frequency and disaster reductions of sandstorm in the arid regions of the middle Ningxia
宁夏中部干旱带生态恢复对沙尘暴的降频与减灾潜力分析

Using the conventional meteorological and anemometer data and the Asian circulation data from 1971 to 2000,as well as the 8-type land use data from 1990 to 2000,an ecological/climatic effect model of sandstorm occurrence frequency and mean duration was established for the spring from March to May in Ningxia region.By carrying out comparison and cluster analysis on the frequency and duration of sandstorms,under different ecological and meteorological conditions,a quantitative relationship between meteorological and ecological factors that result in sandstorms was revealed.The results show that,with the ecological environment being locally improved but degraded as a whole,since the 1970s the threshold of sand flying has been decreasing,the mean duration and frequency of sandstorms have been significantly increasing,and sandstorm damage became more and more severe.Since the middle 1980s,the overall decrease of the sandstorm frequency was resulted from the climate warming and a reduction of cold air activities.However in the area of Yanchi-Tongxin,where the sandstorm frequently occurred and the ecology severely degraded,the ecological degeneration was a major cause of the augmentation of mean duration of sandstorms,suggesting that,in the areas with frequent sandstorms,the improvement and restoration of ecological environment have eminent potential impacts on the reductions of sandstorm frequency and,in particular,mean duration,as well as on the disaster reducing.