Dust storms in Middle Asia: spatial and temporal variations

Dust/sand storms are common events, and one of the most important manifestations of desertification to occur in the arid and semi-arid regions of Middle Asia. Middle Asian deserts are characterized by strong winds, scarcity of vegetation cover, a continental and Mediterranean type of climate with long dry summers, lack of soil moisture and relatively low air moisture, frequent repetition of soil and atmospheric droughts, susceptibility of soils to erosion. Systematic studies of dust storms in the middle Asian region started in the 1930s when "black" and "white" storms increased in frequency. Most of the scientific observations of natural phenomena, including dust storms, in the region ended after the collapse of the USSR, during the 1990s. The main objectives of this study are to monitor and assess the spatial and temporal distribution and activity of dust events over the Middle Asian region. The frequency and spatial distribution of dust storms for three periods of time: 1936-1960, 1936-1980, and 1970-2000 will be shown using meteorological data from almost 500 ground stations and Geographic Information System, (GIS) software. Dust storm activities during these three periods show significant decrease in frequency and considerable changes in the source areas. Temperature and rainfall trends also show significant changes across the region as well as remarkable changes in the annual and inter-annual trends. For the 1936-2000, temperature and rainfall annual trends show three periods of decreases and increases - periods, which correspond to the different atmospheric circulation epochs. This is a future challenge which will be studied in detail. An important goal is to reveal the correlation between the atmospheric circulation patterns (meridional, zonal), synoptic processes and dust storms.