关键词: 盐池地区, 沙尘暴, 变化周期

Abstract: Sand-dust storms are an unexpected result of the desertification process.Climate change(regional and global) and local human activities combine as the primary cause of the frequent storms in northern China.It is important to study the relationship between sand-dust storms and climate factors to gain a deeper understanding of storm patterns.Yanchi County,in Ningxia Autonomous Region is one of the fastest developing regions of sandy desertification in northern China.A detailed analysis of monthly meteorological data from 1961 to 2000 has been undertaken for this region.The results show that drought and wind are the direct causes of sand-dust storms.The frequency of the storms is evidently related to lack of precipitation and days of strong wind.Rainfall at intervals of 1~3 months will significantly retard the propagation of storms.The influence of human action is slowly over-weighing natural factors(rainfall and wind) as the main cause of storms and this indicates a worsening local ecology.The 2~8 year cycle of sand-dust storms is also influenced by El Nino.

Key words: Yanchi County,Ningxia Province, sand-dust storm, changing period