چکیده:
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 generation
of 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.
خلاصه ماشینی:
ir DESERT 17 (2013) 225-231 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) H.
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 generation of dust storms.
In this article it has been tried that with the analysis of data’s gathered from anemometric stations and with attention to threshold velocity in various faces, find a method to discover the regions that are susceptible to generation of flying dusts.
1. Analysis and Drawing of Seasonal and Yearly Wind Roses Figure 3 shows the seasonal and yearly wind roses of the anemometric station of Yazd and shows the direction, velocity, and frequency of the governing winds of the region under study.
Conclusion As the erosion threshold wind velocities of different faces are different, therefore it has been tried that with drawing and analysis of storm roses of various threshold velocities in the region, the particulars of all of faces that generate dust be investigated.
As shown in this figure places that have erosion threshold velocities of less than 20 knots (10 meter/second) have a role in generation of dust and thus the governing winds in this region are able to erode the soil.
Determination of effective places in generation of dust with erosive winds 231References Ahmadi, H.