The regional-scale atmospheric circulation has a main role on the occurrence of dust-storms over the Middle-East. In this section of workshop, I will show you what the structure of low level atmospheric circulation over the Middle East is and how it can affect the formation and evolution of dust events over the area in regional scale. With regard to the topic, first I will have an overview on summer atmospheric circulation over the Middle East. Among atmospheric components, we will take a look on the structure and nature of Arabian anticyclone, Zagros Trough and Turkmenistan anticyclone as a main core of low-level summer circulation. Then, I will draw your attention to the structure of Shamal wind which supposed to be the most important atmospheric component related to the occurrence of dust events. In the second step, I will discuss about the main synoptic patterns related to the occurrence of dust events in the south-west (SW) Iran. I will also try to clarify the source of dust for each synoptic pattern by using a back-trajectory model. It follows by a practical section which we will try to detect the source of dust for a case study by using an interactive back-trajectory model (HYSPLIT) depends on availability.

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