Dust Routing in West and South West of Iran (September 2008)

The monitoring of dust particles by using accurate methods is of great importance. In this study, the role of relative vorticity on dust genesis was evaluated over west and south western of Iran. Moreover, based on Moderate Resolution Imagine Spectro-radiometer (MODIS) imagery, the sequential separation of the dust clouds from bright underlying surface and water clouds is accomplished using Brightness Temperature Difference (BTD). Validations using ground meteorological and air pollution monitoring data over the region indicated the brightness temperature of MODIS bands of 31 and 32 could be matched well with visibility (R2= 0.826). The aerosol optical thickness (AOT) at 550 nm showed very close relationships with the brightness temperature of MODIS bands of 31 and 32 (R2= 0.749). The proposed thresholds of BTD revealed the MODIS images good enough in separating dust from bright surface and clouds, which obviate the deficiency of remote-sensing data products of dust particles near the source. In order to trace the dust dispersion, the HYSPLIT model was applied leading to distinguish Iraq deserts as the main sources of dust over the studied area. The results showed that applying remote sensing data, dynamical evaluation and numerical modeling provided the advantages in enhancing dust measurement capabilities. Statistical analysis of ground based observation suggested the utilization of this approach for dust forecasting in the studied region.