Investigation of the Role of Different Land Uses in a Sand Storm by using Wind Rose and Storm Rose (Case Study: Kashan)

The purpose of this research is to analyze anemometer data to study the wind regime in Kashan and to investigate the role of different land uses in sand storms. Therefore, anemometer data obtained from synoptic station of Kashan were analyzed during a 40-year period (1966-2005) using different methods. Seasonal and annual wind roses and storm roses for different lands were created using WRPlot software (considering the various threshold wind velocity for each area). Finally, the annual wind rose showed that the direction of the prevailing wind in Kashan was from the Northeast, followed by North and Northwest winds. It was shown that the frequency of calm winds was 8.84%. Storm roses that related to the different lands showed that in the pasture lands, the winds of the Northeast, North and West and in incult crop lands and active sand dunes, the winds from the Northeast, North and West had the most role in wind erosion. Also, the risk of soil erosion was not tangible in agricultural lands, sand dunes covered with haloxylon and reg. The drawing of seasonal storm roses in each of the studied lands showed that the erosive winds had the highest frequency during the Spring. In this season, the most erosive winds blow with a speed more than 25 m/s.