Investigation of the sand and dust storms overgreater Mediterranean Basin and determinationof the dust source areas affecting Turkey

Mineral dust particles that are known as one of the most dominant aerosols in the atmosphere are great importance for the Earth ecosystem. The main cause of sand and dust storms is described as drought and desertification. The amount of dust released from the world to the atmosphere is estimated to be approximately 2 billion tons in every year. The amount of annual dust released from the Sahara into the atmosphere is about half the amount of dust released from all sources on earth. The major dust source areas after the Sahara are Middle East, Central and South Asia respectively. Dust emitted from Africa and the Middle East constitutes around 70% of global annual dust emissions. Dust emitted from the deserts to the upper layers of the atmosphere travels long distances. While relatively large dust particles deposit near the source areas, the smaller particles can travel thousands of kilometers. Turkey is exposed to sand and dust storms originating from Africa and the Middle East due to the geographical location. The areas that are close to the Syrian and Iraqi border and the KonyaKaraman Basin are the most affected regions by the dust transport. According to the current climate predictions of the Intergovernmental Panel on Climate Change (IPCC), it is expected that sand and dust storms will be more intense with the increasing frequency and intensity of the drought. iv The spatial and temporal changes of sand and dust storms in the period between 2003 and 2017 for the Greater Mediterranean Basin covering Southern Europe, North Africa and the Middle East were investigated. Satellite Aerosol Optical Depth (AOD) data and the observations of 296 synoptic meteorological stations were used in this study. Analysis data of NCEP-NCAR was also used. It has been determined that the aerosols and mineral dusts in the atmosphere do not show a significant change globally in recent years. On the other hand there have been significant decreases and increases in the regional scale. Significant increases were generally calculated on the Arabian Peninsula, the Bay of Bengal and the eastern coasts of Asia. In the calculations, very high correlations were found between the measurements of the satellite Aerosol Optical Depth (AOD) data and observations of the synoptic meteorological stations, especially in the dust source areas and around these regions with a 95% confidence interval. According to both satellite AOD data and synoptic meteorological observations, there was no significant change in the North African atmosphere between 2003 and 2017, while there was a rising trend in the Middle East, which started in 2007, ended in 2012. After this increasing period, there has been decreasing trend since 2013 in the Middle East. In the south of Europe, it has been found that the aerosols in the atmosphere tend to decrease significantly over the years. It was found that the sea level pressures decreased in the most of the Greater Mediterranean Basin when the number of dusty days and AOD averages increased in the Middle East Basin (2008-2012). Decreased pressure values show that low pressure systems are more effective in this period. The relative humidity and soil moisture averages for the same period (2008-2012) were also calculated under the long term averages.