Use of Anemometric Results and Threshold Velocities for Determination of Proper Regions Where Sand Storms are Generated (Case Study: Around the Synoptic Station of Yazd)

In order to recognize the wind erosion situation of a region, the survey of its windiness is not sufficient and the physical characteristics of earth are of importance too. In fact, the outbreak of dust storms in a region is due to the sensitivity of earth and domination of wind in that region. In this investigation we have tried to find a way for determining the regions in which a dust storm is generated. In addition to wind rose that determines the windiness of a region, we have used another graph with the name of storm rose. With this new graph we have tried to find a relationship between the earth surface situations (threshold erosion velocity) and windiness of a region, so that we can reach a more suitable analysis for wind erosion. Studies made in the region show that where the threshold velocity less than 8 m/s (16 knots) is, the land is susceptible for erosion and thus has an important role in generationof dust storms. With the Storm roses drawn, it was also distinguished that most of the dust storms evolved in the region have the directions between west and northwest. So if we want to lessen the damages of flying dust and particles on Yazd city, we should stabilize the dust in the above-mentioned direction and bring them under control.