Spectral and synoptic analysis of Haboob in Tehran, Iran

On 2 June 2014, a Haboob dust storm occurred in Tehran, which lasted less than 2 h, caused severe damages to the properties and involved loss of human life. This paper describes the behavior of this Haboob dust storm, by analyzing of metrological satellites data, as well as assessing the mesoscale and microscale patterns that led to the occurrence of the dust. A dust detection scheme was developed to monitor the dust formation using the Infrared (IR) channels of the Spinning-Enhanced Visible and Infrared Imager (SEVIRI), carried on board MSG satellites. Restrictive thresholds were placed on the individual components to maximize detection success, and to minimize the misidentification of dust. The results indicated cold and strong downdrafts along with the cold front activity during the maximum temperature over the central hot desert caused a strengthened and intensified wind velocity that led to a strong Haboob in Tehran province. The synoptic analysis indicated that a low-pressure system stretching from the southeast of Iran to the northwest of Iran and Iraq was the dominant feature, despite the presence of a weak high-pressure in the center of Iran. The satellite analysis indicates an extreme dustiness discernible in the southwest of Tehran following the formation of a convective storm; however, uncertainty in dust identification increases as the IR dust signal weakens because of underlying dust cloud beneath the thick convective clouds. The analysis of could physical properties reveals the formation of a convective storm after dramatically decrease in cloud top temperature (CTT) and cloud top pressure (CTP), and increasing the cloud optical depth (COT) which led to development of an overshooting cold cloud over Tehran province before dust formation.