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Elemental tracers for saharan dust

Çetin, Kocakaya Banu
The impact of Saharan dust on the ecology in the Mediterranean region had been extensively discussed in the literature. However, in most studies in this field, dusts collected on aerosol filters are assumed to have Saharan origin. Although this assumption is correct during Saharan dust episodes, dust locally produced at the arid eastern Mediterranean basin should be the main soil component in the atmosphere during most of the year. In this study, concentrations of elements and ions measured in aerosol samples collected in 1992-1993 and 1998 in Antalya station were investigated in order to understand the source regions of aerosols and potential elemental tracers, which can be used to differentiate between Saharan and local dust components at the Eastern Mediterranean region. Collected and measured samples were statistically examined for 41 elements and ions. In addition to elemental tracers, potential for soluble-to-insoluble P ratio as a tracer was also investigated. mProbable source regions at North Africa from where dust impacting Eastern Mediterranean originates by trajectory statistics. Backtrajectories, which are essential in such study, were calculated using a three-dimensional isentropic trajectory model. Monthly distribution of Saharan dust events shows that Saharan dust events mostly occurs in spring and fall and rarely observed in winter probably due to scavenging of dust particles by frequent rain events in winter. Based on the backtrajectory analysis, enrichment factor calculations and results of multivariate statistical techniques, Cr, Ni, Ca, Mg, Cs, K, Co, Rb and Nd are identified as potential tracer, to differentiate Saharan and local soil in the eastern Mediterranean atmosphere.