Investigation of dust storms in Ilam and the performance analysis of simulation of 6 numerical prediction models at a severe dust storm in west of Iran

Many countries in the arid and semi-arid regions of the world encounter dust storms phenomenon, that is one of the meteorological problems leading to daily life disturbances, financial losses, public health risks and the destructive environmental impacts. Although the dust storm is historically recorded as an old event in some provinces of Iran, nowadays it becomes a new event in the other provinces such as Ilam in the west of Iran. Dust storms have been remarkably increased since 2007 in a period of 20 years (1997-2017) of daily frequency of dust storms in Ilam station. The dust storm is mostly observed in Ilam city (center of Ilam province) in 2011, after the years of rainfall deficiency. After statiscal investigation of dust storms in Ilam province and factors affecting its formation, the dust storm from 3nd to 6th July 2016 are studied that reduced visibility so much in West and SW of Iran. On the of 3rd- 4th of July of the same year, the intensity of the dust storm was so high that made the visibility decresses severely in Ilam city. The source of this dust storm was the eastern areas of Syria and central Iraq. This fact also appeared in the satellite images and in the output of HYSPLIT MODEL. The output of WRF-Chem Model clearly shows the dust mass over East-Syria, Central and East Iraq and West and SW Iran. Model outputs in intensity of surface dust concentration of MACC-ECMWF, NASA-GEOS, NCEP-NGAC, NMMB-BSC, and BSC-DREAM8b models are compared to the observation of the aerosol concentration in Ilam city and results show that NASA-GEOS model has better performance, based on the results compared to the other models.
In display of dust dispertion on Iran, the middle of all models is more compatible with reality.