Numerical Simulation of Extreme Sand and Dust Storm in East of Iran, by the WRF_Chem Model Case study; 1 May & 1 June 2011

Iran location in the desert belt is accompanied with frequency increasing the sand and dust storms, especially in the eastern and southern areas and created adverse environmental effects. One of ways to study this event is dust simulation and forecasting. Aim of this study, Weather Research & Forecasting-Chemistry coupled model (WRF-Chem.3.6.1) is used to simulate, forecast and design alerting system for sand and dust storm events (East of Iran). In addition, dust concentration data that were collected by environmental protection organization (EPO), wind speed and direction data from the Meteorological Organization and MODIS images are used to investigate transport path of storms and have better forecast and right time alerting. True color images by software ERDAS IMAGIN queries to identify dust source. Results showed that the main dust and sand emission source in Sistan is dry bed of Hamoun wetland. Also during the storms that are investigated in this study, transport of dust clouds are observed to southern part of Iran up to Oman sea because of converging currents north-south winds on Eastern part of Iran (especially in spring and summer) that create strong winds in lower levels of atmosphere. This wind are responsible of increasing dust emission. WRF-Chem model had reasonable estimation related to spetial and temporal scale in the study area. Due to use of global forecasted data as model input data, it was expected to observe bias in concentration estimation from real situation. The model was run for 30 km spatial resolution and results revealed storm formation in Sisitan affected by local geographical properties especially topography features.