부산대학교 도서관

The interest of investigating the phenomenon of dust storms comes from their direct impact on human and ecosystem health and climate global change. Despite that the majority of previous investigations performed in many parts of the Middle East, Africa and China, however the main source regions of dust storms in Iraq and the processes that govern their evolution have not been well studied, making their effects an important fact of uncertainty in future dust storms predictions in the region. The key importance of this study is determining the meteorological, source regions and transport pathways. The analysis in this work was based on a 3 hourly meteorological dataset (dust storms, wind speed and wind direction observations) collected over a 29 year period (1985-2013) which was obtained from the Iraqi Meteorological Organisation (IMO), for which systematic observations were available for 11 ground surface stations across Iraq. As well as that this thesis investigated in the Iraqi dust storms events from SEVIRI (Spinning Enhanced Visible and Infrared Imager) satellite data point of view, the ECMWF (European Centre for Medium-Range Weather Forecasts) 10m wind-field reanalysis data and air mass history of backward and forward trajectories from the HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model. Dust storms were found to be highly associated with north-westerly winds and are often associated high wind speeds (15-20 ms-1). Dust storms were observed to be more frequent during March-September, particularly in the daytime (06:00-15:00) and that they are short lived (< 6 hours) with the period of greatest frequency being between (0-3 hours). Source region of large dust storms (12 major dust storms) was identified based on a dust characterisation using the absolute radiance difference of (12.0-10.8 μm) and (10.8-8.7 μm), in addition to (10.8 μm) from the SEVIRI. The early stages of the 12 large dust storms were investigated, the development of the storms was tracked and the main source region explored. A frequency distribution of the occurrence of dust in all these storms revealed that the source region was consistent across all storms and was centred on the Euphrates River basin (34.20.00°-36.50.00° N to 38.00.12°-41.00.20° E) on the Syrian-Iraqi border. This region has been subject to recent conflict and hence reduced agricultural development but also has received reduced water supply due to upriver water management in Turkey. This work shows that these changes have given rise to an increase in major dust storms and identified the region as the major cause of large dust storms across Iraq. All of the 12 major dust storms were generated during periods when the region was impacted by low pressure systems that had travelled eastward from the Mediterranean Sea and were highly associated with the Shamal north-westerly winds causing massive dust concentration along the most populated region in the valley of the Tigris and Euphrates Rivers of the Alluvial Plain. The advection of large storms carried on and ended up in south and south east of Iraq, Kuwait, The Arabian Gulf and Iran. The outcomes presented in this thesis offer new insight for dust storms studies in Iraq regarding where are major regions of dust storms, on why the Euphrates River basin has become an important source of dust outbreaks and on what are transport pathways of large dust storms events. Therefore, an increasing demands in future dust storms predictions and forecasting in the region can be raised and consequently, this could probably lead to further investigations on the significant of dust impacts on human in the region and the utility of using satellite and surface data in dust applications.