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Air-to-snow mineral transfer of crustal species on the Greenland Ice Sheet was studied at Dye 3 during a full annual cycle (August 1988–August 1989) and at Summit during a summer campaign (May 1991–September 1991). 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 snows (32 precipitation events) reveals the same seasonal picture. Furthermore, 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 cycle 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 elements, such as Fe or Al, in Arctic snows accurately reflects the seasonal atmospheric signal of mineral aerosols. |
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