AIR-TO-SNOW MINERAL TRANSFER - CRUSTAL ELEMENTS IN AEROSOLS, FRESH SNOW AND SNOWPITS ON THE GREENLAND ICE-SHEET

Air-to-snow mineral transfer of crustal species on the Greenland Ice S heet was studied at Dye 3 during a full annual cycle (August 1988-Augu st 1989) and at Summit during a summer campaign (May 1991-September 19 91). At Dye 3, continuously sampled aerosols (54 filters) show a clear seasonal cycle of insoluble mineral elements (Al, Fe, Ca) with strong concentration peaks in April. The simultaneous collection of fresh sn ows (32 precipitation events) reveals the same seasonal picture. Furth ermore, a comparison of metal concentrations in both aerosol and snow indicates that the transfer of crustal elements (Fe or Al) from air to snow seems to occur without fractionation. This one year seasonal cyc le Is recovered in snowpits excavated at Dye 3 (1 yr) and at Summit (3 yr) exhibiting no major post-depositional changes of crustal elements in aging snow. This suggests that the insoluble fraction of crustal e lements, such as Fe or Al, in Arctic snows accurately reflects the sea sonal atmospheric signal of mineral aerosols. (C) 1997 Elsevier Scienc e Ltd.