Synoptic aspects associated with pervasive dust storms in the southwestern regions of Iran

Dust storm is a natural hazardous phenomenon that affects arid and semi-arid regions of the world same as Iran. The present research aims to investigate formation synoptic patterns pervasive dust storms (PDSs) in southwestern For this purpose, daily data visibility less than 1000m 16 stations (Ilam Khuzestan provinces) were reviewed during 2004–2017, 59 PDSs with more 2 days duration (overlapped: 70% region) extracted. In practice, mid-level atmospheric (500, 700, 850 hPa, sea level pressure (SLP)) 2.5*2.5 degree resolution (domain: 0-80°E 10-70°N) obtained from NCEP/NCAR reanalysis dataset, matrix 825*59 500 hPa was performed. Principal component analysis (PCA) S-mod, used for extracting make PDSs. PCA showed first four components ensured 86.45% variance. classification based on output had seasonal structures. Synoptically, north wind blowing pattern most dominant structure Middle East. second third postfrontal fourth prefrontal reason cold seasons year. From final patterns, three dominance Persian trough SLP maps. Mean values map aerosol optical depth suggests each consistent stimulates special centers.