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    CHARACTERISTICS OF RED RAIN IN THE CILICIAN BASIN, NORTHEASTERN MEDITERRANEAN
    (Nova Science Publishers, Inc, 2009) Oezsoy, Tuerkan; Oernektekin, Sermin
    The northeastern coast of the Mediterranean Sea is tinder the influence of sporadic dust transport from North African (The Great Sahara) and Middle Eastern (Arabian Peninsula) deserts, particularly during spring and autumn. Mineral dust from these and regions typically has a characteristic reddish yellow - reddish brown color owing to its high iron oxide content. Precipitation samples collected at Mersin, on the eastern Mediterranean coast of Turkey, during the period of December 2003 - May 2005 have been analyzed with respect to their red dust contents, and in relation to backward air mass trajectories corresponding to the rainy days to determine potential source regions. Classification of trajectories revealed local sources from Anatolian mainland and in the Cilician Basin, in addition to remote sources in North Africa and the Middle East. Approximately, one fourth of the precipitation samples can be classified as red rain, annually. The mean electrical conductivity and the volume weighted mean (VWM) Aluminium (Al) concentration of red rain were found to be more than four and eight times higher than normal rain, respectively; while the dissolution of calcite in dust was found to result in an order of magnitude decrease in the VWM hydrogen ion concentration of red rain, by neutralizing (buffering) the acidity of rainwater. Due to dissolution of atmospheric CO2 in rainwater, natural precipitation is slightly acidic (pH approximate to 5.6). The VWM pH values were calculated to be 6.10 for normal rain and 7.21 for red rain. The mean bicarbonate concentration of red rain, estimated from the theoretical relation between pH and HCO3-, was sixteen times higher than that of normal rain. Similarly, abundance of the major anions (Cl-, NO3-, SO42-) and major cations (Na+, K+, Ca2+, Mg2+, NH4+) measured in red rain samples were all high, relative to the values observed in normal rain samples, including formaldehyde (HCHO), the only organic parameter measured in Mersin precipitation. Similar enhancements were also observed in soluble (Al-s) and particulate (Al-p) aluminium species. Based on these results, red rain can be identified as a rich source of all major ions, formaldehyde and aluminium suggesting mineral dust particles to act as host for all measured species in the northeastern Mediterranean atmosphere.
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    Red Rain in the North-Eastern Mediterranean
    (Foundation Environmental Protection & Research-Fepr, 2008) Oezsoy, Tuerkan; Oernektekin, Sermin
    North Eastern Mediterranean is under the influence of sporadic dust transportation from desert sources in North Africa (The Great Sahara) and the Middle East (Arabian Peninsula) particularly during the spring and autumn. Mineral dust originated from these arid regions has characteristic reddish yellow-reddish brown color due to its high iron oxide content. Following atmospheric transport, mineral dust settles by either dry or wet (washout or rainout) deposition mechanisms. Precipitation samples collected it Mersin on the Eastern Mediterranean coast of Turkey during the period of December 2003-December 2004 have been investigated with respect to their red dust contents, Backward air mass trajectories corresponding to the rainy days were analyzed to determine potential source regions of red dust transported to the Northeastern Mediterranean. Approximately, 1/4 of the total precipitation samples can be evaluated as red rain. The mean electrical conductivity arid the volume weighted mean Al concentration of red rain was found to be approximately seven times and five times higher than normal rain, respectively; while the dissolution of the calcite in dust has caused an order of magnitude decrease in the volume weighted mean hydrogen ion concentration of red rain, by neutralizing (buffering) the acidity of rainwater. Due to dissolution of atmospheric CO2 in rainwater, natural precipitation is slightly acidic (pH approximate to 5.6). In this study, the volume weighted mean pH values were calculated to be 6.09 for normal rain arid 7.27 for red rain. Using Al concentration of precipitation samples, wet deposition flux of mineral dust during 2004 was found to be 2.13 g m(-2) yr(-1). If dry deposition flux is added to this value, a total flux of 4.84 g m(-2) yr(-1) is found for atmospherically transported mineral dust.