تعيين شدت فرسايش بادي در منطقه كاشان با استفاده از مدل بيايان زايي

Intensity Determination of Wind Erosion in Kashan Area by the Deseretification Model

Erosion is a phenomenon during which soil and sediment materials are transferred by such damaging factors as water and wind. The type of erosion, of course, is different in various climates. As an example, in wet and semi-wet areas, water erosion is more likely than wind erosion. In turn, wind erosion is the main reason for damaging and transferring soil and sediment materials in arid and semi-arid zones, which can cover talented lands and bring about indispensable damage to land administrators. Wind erosion in arid zones is one of the most important processes of desertification, which is considered in different forms and in various models. One of the main methods is FAO-UNEP method, which is considered the most complete and comprehensive method for desertification up to now. However, analysis made on the wind erosion process showed that some of its criteria had deficiencies that were reviewed, and some of them, that were suitable for studying area were selected and applied. Another method that was presented for evaluating the intensity of desertification is ICD, in which more attention is paid to special conditions of the area biomes. An analysis made on this method indicated that the number of criteria considered for evaluating the wind erosion were not sufficient, and due to small scale of the method (1:250000), the available criteria were evaluated qualitatively and in the overall form. From the analysis made on both methods, suitable factors were selected in order to determine the intensity of the regionʹs wind erosion, giving value to each of the standards and sub-factors in the form of a desertification model. After determining working units (geomoprphologic facies), all criteria and sub-factors were evaluated in each facies and then across the region. Among the whole area understudy(616.81 km^2), about 118.2km^2 (I9.16 percent) was found to be in very high class, about 316.81 km^2 (51.36 percent) in high class and 181.8km^2 (29.48 percent) in middle class intensity of wind erosion.