Tropospheric aerosol at Terra Nova Bay (Antarctica): Geochemical components and their time distributions during four summer seasons

Four aerosol sampling campaigns were performed in the summer season (November to February, 93/94, 94/95, 95/96, 97/98) with a 12 h sampling time at a coastal site near to the Italian base of Terra Nova Bay. Despite the low aerosol concentrations. PIXE analysis allowed in all campaigns a principal components analysis based on elements Na, Mg, Al, Si, S. K, Ca and Fe, in which three principal components (PC) contribute at least 95% of the total variance. Each one of the six elements Na, Mg, Al, Si, S and Fe is significantly (greater than or equal to 0.994) correlated to one of those PCs. This fact. together with the structure of the elemental profiles of the PCs, allows their geochemical identification with non-sea-salt S, sea-salt and crustal aerosol. Elements S, Na and Fe are convenient tracers of these PCs. One campaign displays however an anomalous structure of the two PCs of marine origin. A large Cl depletion of the sea-salt aerosol is observed. The time distributions of the concentrations of elements Na and Fe display in all campaigns several peaks of short duration (a few 0.5 days units). The concentration of element S always displays a continuous and generally time-varying background with the superposition of a few peaks. (C) 2002 Published by Elsevier Science B.V.