Statistic and Synoptic Analysis of Dust Phenomena in West of Iran

A dust storm is a meteorological phenomenon common in arid and semi-arid regions. Dust comes from arid and dry regions where high velocity winds are able to remove detached particles mostly silt and clay sized material. Dust consists of particles in the atmosphere that arises from various sources such as soil and lifted up by wind. The Sahara and dry lands around the Arabian Peninsula are the main terrestrial source of airborne dust, with some contributions from Iran, Pakistan and India into the Arabian Sea. In addition, China’s significant storms deposit dust in the Pacific. The term dust storm is more likely to be used when finer particles are blown long distances, especially when the dust storm affects urban areas. Dust has been known as one of the atmospheric features in West and South West region of Iran, which in recent years has increased its affecting severity, steadiness and area expanse. Iran and particularly west and south-west of Iran, periodically faces with the dust phenomenon and its problems. West of Iran considering its natural area and being near the sources of dust in the West Asian region is prone to frequent occurrence of the dust phenomenon. United Nations Development Program (UNDP) in a report about drought in the southwestern region of Iran and neighboring countries such as Iraq stated that having been associated with surface and subsurface moisture loss and also losing vegetation covers, are the main causes of increasing dust phenomena. Also outlined fine- grained texture sediment surfaces with human factors such as the construction of massive dams on the rivers leading to the basin of Mesopotamia (Iraq) by countries in the region. Therefore, the results of the dam's construction are low water entering the wetlands of Mesopotamia. Also a significant proportion of the sediment surfaces which had been under the water bodies in previous years, has been suffered by severe erosion through local and regional winds in recent years. Particles entering the atmosphere and flowing into the West of Iran are sometimes moved to the center of country. According to the importance of this phenomenon and the problems that have been established in different areas, in this study, we attempted to first, do statistical analysis of the dust phenomenon, and frequency of its occurrence in the past and present, and also to recognize regions of dust sources and the weather conditions, then diffusion patterns and dust storms routing have been analyzed through the combined methods.