Simulation of dust emission from the Turkmenistan desert to the southern coast of the Caspian Sea

In the recent decade, the southern coastal of the Caspian Sea is frequently facing dust hazards. This research attempts to identify the original source of dust generation that causes dust transmission to the southern coastal of the Caspian Sea in 19th and 20thof September 2014, and analyze the atmospheric circulation that leads to the emission of dust into this area. Therefore, Implementation of the HYSPLIT backward Lagrangian model is used, for determining the origin and direction of dust flow, the chemical atmospheric model (WRF-Chem) is applied to determine the concentration and distribution of dust, and to simulate the system’s pattern. The results indicate anew source of the dust in the eastern part of the Caspian Sea and across the deserts of Turkmenistan and Qara-Qum. The main cause of this dust event is the formation of thermal cyclone on the warm area in the eastern part of the Caspian Sea. Surface convergence due to cyclonic circulation of the low pressure and also dry desert coverage, caused dust transfer into the atmosphere column.Negative components of U-wind and V-wind at 10m height and increase in wind speed due to the intensified pressure gradient over the desert in the east of the Caspian Sea; lead to the formation of the Northeastern streams (Westward) and dust emission into the southern coast of the Caspian Sea. The Monitoring of Visible images from MODIS sensor and zoning of AOD confirms the results of numerical simulations in dust transformation to the northern slope of the Alborz Mountains.