Saharan dust transport event characterization in the Mediterranean atmosphere using 21 years of in-situ observations

Abstract. The Mediterranean Basin is regularly affected by atmospheric dust transport from the Saharan desert. These recurring events have strong implications for the Earth’s energy budget, cloud formation processes, human health, and solar energy production. Monte Cimone, with 2165 m a.s.l., is an ideal platform to investigate dust outbreaks in Mediterranean Europe. In this study, we present 21 years (2003–2023) of dust transport event identification, derived from continuous measurements of the aerosol optical size distribution coupled with backward trajectories. Throughout all the years investigated, the fraction of dust transport days remained constant at values between 15 % and 20 % without any detectable trend. This absent trend was also observed in the particulate matter concentration. The annual cycle of dust transport days was characterized by two peaks from May to August and in October and November with values up to 20 %. A similar annual cycle was reflected in the particulate matter concentration with the highest concentrations in summer and the lowest in winter. Grouping consecutive dust transport days into dust transport events revealed that in the winter months a typical event had a duration of one or two days, whereas in the summer months dust transport events lasted longer (three or more days). The 21 years of measurements presented in this study will set a baseline to assess future dust transport scenarios. Furthermore, they can be used to validate dust forecast models to increase the accuracy of predicting atmospheric dust transport towards the Mediterranean Basin.