Abstract: A set of 22-year data from an Observation Station located in Ulanbuh Desert,which belongs to the Desert Forest Experimental Center of Chinese Academy of Forestry and the Weather Station of Dengkou County,Inner Mongolia(from 1954 to 2003) were used to analyze yearly and seasonal changes of dust events in Ulanbuh Desert.The results showed that dust events mainly occurred from February to June,accounting for 58.5% of the total events in a year,among which April was the severely attacked month.The times of dust events in winter were less than that in spring,and the least in autumn.Dust events occurred frequently during middle 1980s.The annual dust days were about 100 d(164 d in 1986) in the period from 1983 to 1987.The frequency of dust storm decreased significantly during early 1990s and dropped to a very low level in the middle and late 1990s,but it has been increasing from the beginning of this century.The times of dust events from Feb.to Jun.have evident positive correlation with wind speed,evaporation,air/ground temperature,but have evident negative correlation with relative humidity of atmosphere,ground temperature and precipitation.The rich sand sources combining with the dry climate in the studied area contributed to the increase of dust and sand storm events.

Key words: Ulanbuh Desert, west of Inner Mongolia, dust event, weather condition