Synoptic analysis of Iran’s northwest dust storms

This study was conducted to identify the effective synoptic patterns in creating dust storms using hourly visibility data and considering the meteorological codes related to the dust phenomenon in 8 meteorological stations located in East and West Azerbaijan for a period of 14 years (1996-2010). Then, using the network data of the US Center for Atmospheric and Oceanic Forecasting, the scan-synoptic characteristics of each dust storm were analyzed. The determination of the main sources of dust for each of the selected storms was performed using the Lagrangian model of dust particle tracking and using the regression tracking method. The results show that most dust storms in the northwest of the country occur in spring and May. Also, 2008 and 2009 had the highest frequency of dusty days. The synoptic view found that the pervasiveness, durability, and intensity of dust storms were consistent with the location of low-pressure surface systems located in western and southwestern Asia. In the synoptic study of the association of dust storms, 3 sea level pressure patterns with different arrangements were identified as the main patterns at the time of the storms. The results show a strong pressure gradient due to the expansion of warm low pressures from southern latitudes and cold high pressures from high latitudes to the west and southwest of Asia and the rise of dust particles from the ground and dust currents blowing towards the research area with The southwest-northeast direction is by low depth trough based on dust sources in Syria, Iraq and Saudi Arabia in the middle levels of the troposphere.
Key words: Dust storm, Low pressure, LAGRANGIAN particle tracing model, low depth trough, North West of Iran
Key words: Dust storm, Low pressure, LAGRANGIAN particle tracing model, low depth trough, North West of Iran