Abstract
The first 10 days of September 2015 were marked by intense dust activity over the Middle East and the Arabian Peninsula. This study examines the atmospheric conditions at the origin of the large dust storms during this period. We particularly investigate the atmospheric dynamics leading to the development of a large dry cyclone over Iraq on 31 August 2015 which in turn generated an intense dust storm that affected most of the countries around the Arabian Gulf and lasted for 5 days. We found that the cyclone developed over Northwest Iraq as a transfer to low levels of a cut-off low which had formed two days earlier at upper levels over Turkey. Large dust loads exceeding 250 tons were emitted and moved southeast in a cyclonic shape toward the Arabian sea. The second large dust storm on 6-8 September 2015 occurred over Syria and affected all the coastal countries on the eastern side of the Mediterranean Sea. It was associated with the occurrence of a series of density currents over northeast Syria emanating from deep convection over the mountainous border between Syria and Turkey. The unusual development of deep convection over this area was associated with a blocking high and interaction with orography. Both the cut-off high and the cut-off low occurred during a period characterized by a meandering polar jet and an enhanced subtropical jet causing unstable weather over mid-latitudes which in turn led to highly polluted atmosphere by natural dust in the affected countries.
Highlights
Mineral dust plays a key role in the Earth’s system
This study examines the atmospheric conditions at the origin of the large dust storms which that has grown out of a ridge and become displaced out of the basic westerly current and lies poleward occurred during the first 10 days of September 2015 in the Middle East
In a for the first time the atmospheric dynamics leading to the development of a dry cyclone over Iraq in cut-off high situation, the convective activity and related precipitation are usually shunted around the
Summary
Mineral dust plays a key role in the Earth’s system. Despite being emitted from relatively limited areas around the globe, dust aerosols impact the climate regionally and globally by virtue of their transport over long distances and interaction with radiation and clouds during their presence in the atmosphere. 20% of dust events, are related to Saharan cyclones and that when considering only extreme dust events, the contribution of Saharan cyclones reached 70% Despite their effective role in dust emission and transport over long distance, no attention has been given to dust activity associated with cyclogenesis in the Middle East, one of the major dust sources on a global scale (e.g., [35]) and where cyclones are a ubiquitous feature. We investigate, for the first time the formation of a cyclone over Iraq (Figure 1b) and deep convection generating density currents over Syria (Figure 1c) to highlight the mechanisms leading to their occurrence and their role in the observed high dust activity in September 2015 in the Middle. East 2015, MODIS satellite images the development cyclone over on 31 August South on its
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