Satellite-synoptic monitoring of dominant dust entering western Iran.

Abstract

Dust storm in Iran's western regions has been one of its major environmental problems in recent years, which has not only turned into a yearly phenomenon but is also expanding. This study investigated two events of dominant dust in southwestern Iran using moderate resolution imaging spectroradiometer imagery, Reanalysis Datasets (meteorological fields and atmospheric compositions), in both hot (July 2, 2008) and cold (February 18, 2017) seasons. After radiometric correction and calculation of brightness temperature as well as the reflective and thermal behavior of dust, the research results showed that the detection of dominant dust entering was 0.645 μm (visible red) and 0.858 μm (near-infrared) in the reflective ranges and 3.959, 8.55, 11.03, and 12.02 μm in the thermal ranges. Synoptically, the lower values for mean sea level pressure from the east Mediterranean along Syria and Iraq to the southwest and Central Asia facilitate a convergence condition in the lower troposphere that induces strong northwesterlies, Shamal winds, over the Middle East toward the Persian Gulf, forming a more expansive aerosol hotspot over southwest Iran. However, on a cold day, high dust events in Arabia and south Iran are related to the ongoing high pressure, which is accompanied by a subtropical jet, following anticyclonic circulation toward southwestern Iran.