Analysis of the Seasonal Variation in Dust, Cl−, NO3 −, and SO4 2− in Two Central Greenland Firn Cores

Abstract

The concentrations of dust, Cl−, NO3 −, and SO4 2− in two firn cores covering the period A.D. 1891 to 1910 have been analyzed and compared. The cores were drilled 130 km apart – one west and one east of the north-south ice crest in central Greenland. The dust concentration is higher at the western site. This suggests a greater influence of continental aerosols in precipitation there, and that most of the dust comes from the west. The Cl− concentration is higher at the eastern site in some years, probably because of greater marine influence on that site. Both sites have similar concentrations of NO3 − and SO4 2−. A rise in SO4 2− concentration in the middle of the period is explained by volcanic activity and increasing anthropogenic influence. The seasonal variation in each component is discussed, and explained within the framework of an Arctic aerosol-reservoir model.