Climatic factors affecting dune mobility in the west of Khorasan Razavi Province, Iran

Dust, considered as one of the important causes of land degradation, covers extensive areas of the west part of Khorasan Razavi Province. Much of the dust can be stabilized with a type of vegetation, which depends on climatic factors mainly wind power and rainfall. Changes in these two factors affect other factors such as temperature, evaporation, relative humidity, which lead to drought and can have serious consequences for man and environment. The present study aims at the climatic factors affecting dust in the west of Khorasan Razavi Province. At first, yearly as well as monthly data were prepared for the meteorological stations, and then the relationships among the number of dusty days, climatic factors and drought index (SPI) were investigated. Moreover, drought severity index (DSI) was calculated to study the frequency and intensity of dust, and the regression coefficients of the indices were obtained. The investigation of the trend of climatic changes in almost three decades in the western cities of Khorasan Razavi indicated that the conditions were favorable for increasing dust. Additionally, the results showed that a significant positive correlation between the increase of dust and DSI on one hand and the days with horizontal visibility less than 200 m.