Saharan Dust Input to the Western Mediterranean: An Eleven Years Record in Corsica

Abstract

An 11 years survey (1984–1994) of the Saharan dust input was performed in Corsica, on an event basis. Dry deposition was collected separately manually since 1985. Wet deposition of dust particles is independent of the amount of rainfall. Dry deposition seems to be of minor importance in Corsica, which could be related to the high altitude of dust routes above the Mediterranean, the efficiency of dust particles acting as condensation nuclei, among other parametres. Dust fallout events are very brief (usually less than 3 days long) and irregular in intensity and temporal pattern. A seasonal pattern appears in the frequency and magnitude of events (spring and autumn maxima) but with a very high variability (monthly input σ > 100% in spring). The high magnitude events drive the variability of the dust fallout at the annual and interannual scale. The annual input of Saharan dust varies between 4.0 and 26.2 g m⁻², depending on the occurrence of high magnitude events. The annual average value for the period studied is 12.5 g m⁻². The annual input seems to decrease in the 1990’s. If we consider that the Saharan dust input to Corsica follows the same patterns as those recorded in the Alpine glaciers, we can assess that the maximum input during the last 40 years occured in the 1980’s.