Severe dust storms in Central Asia

The study of the spatial distribution of the severe and very severe dust storms over the Central Asian area has been carried out. The dust storm event can be considered as severe if it lasts 3–12 h, storms with wind speed 10–14 m/s and meteorological visibility in the range of 500–1000 m. The extremely severe dust storms last more than 12 h, with the wind speed exceeding 15 m/s; the dust storms with meteorological visibility less than 50 m are considered as very severe regardless to duration and wind speed. The data of daily meteorological observations from 144 meteorological stations of Kazakhstan and 29 meteorological stations in Uzbekistan and Turkmenistan for the period 1936–1972 had been analyzed, and number of days with severe and very severe dust storms had been calculated using above criteria. Relation between the number of days with dust events and number of severe and very severe storms was calculated, and map of spatial distribution of severe events in Central Asia was compiled using this relation. The analysis of extremely severe dust storms, which developed under the exits of southern cyclones, was done.