Saharan dust episodes in Hungarian aerosol:: elemental signatures and transport trajectories

In the present work the episodic appearance of Saharan dust in the Hungarian aerosol has been investigated using our 1991-2000 aerosol data obtained with proton-induced X-ray emission elemental analysis. For selecting local episodes of Saharan origin three different approximations have been applied. On the one hand, episodes have been selected in the time series of concentration ratios Ti/Ca, Si/Al, Al/Ca, Ti/Fe, Si/Fe, Ca/Fe generally accepted as regional signatures of Saharan dust. Remarkable similarity has been found between Italian and Hungarian observations of Saharan dust episodes in spring 1991. The tracing power of the regional signatures generally accepted as fingerprints of Saharan dust was found to be limited in the present region due to anthropogenic effects during transport. On the other hand, either backward air trajectories or TOMS aerosol index data from NASA satellites NIMBUS7 and EARTH PROBE have been used as additional tool for assigning local effects to Saharan sources. A nine-month overlap in the application of trajectories and TOMS maps permitted us to compare the applicability of these selection tools. During the period considered we assigned nearly 50 local episodes to Saharan sources. Data are presented for the frequency, the probable source areas and the seasonal distribution of Saharan episodes in the Hungarian atmosphere. (C) 2004 Elsevier Ltd. All rights reserved.