Monitoring and Forecasting of Effective Climatic Factors on the Mobility of Sand Dunes in Semnan province

Wind erosion and the movement of quicksands are considered as one of the important processes of land degradation and a serious challenge in Iran. In this study, an attempt was made to estimate the frequency of dust days in synoptic stations of Semnan province by considering the weather conditions. Also, the activity of sand dunes based on Lancaster index was examined. The results of this study during the statistical period of 15 years (2003-2017) showed Damghan station with 10% of erosive winds and 1058 days with dust and Shahroud station with 1% of erosive winds and 58 days with dust and Dust has the highest and lowest percentages of winds with speeds higher than the wind erosion threshold, respectively. The results of Lancaster index showed that Damghan city with the highest index has the potential of "fully active" wind sediments and therefore the stabilization of sand dunes is essential to reduce the damage caused by the activity of sand dunes in this area. The results of predicting the effects of possible changes in climatic factors on the mobility of quicksand in the selected station of the province showed that the sensitivity of sand mobility to changes due to increase in rain more than wind speed and to changes in decrease due to rain less than wind speed and if the average wind speed decreases by 30% in the future or the amount of rainfall increases by 30%, the condition of the hills will change from fully active to active.