ARCTIC AEROSOLS IN GREENLAND

Elemental composition of Arctic aerosols is being studied on the Green land Icecap and in northeast Greenland to determine the level, composi tion, seasonal variation and origin of the aerosols, of which little i s known in the remote and elevated central region. In particular, the degree of penetration of arctic haze aerosols is of interest since thi s may cause perturbations of climatic parameters. Arctic haze aerosols have previously been found at four coastal sites notably in north Gre enland. Receptor modelling of the aerosol by factor analysis revealed three to five components of remote origin from both natural and anthro pogenic sources. In north Greenland the anthropogenic components exhib ited large annual cycles with pronounced maxima in winter caused by lo ng-range atmospheric transport from midlatitude areas. These measureme nts have been resumed as a reference to the Icecap Experiment. On the Icecap, aerosol samples are being collected in two size ranges on a co ntinuous basis concurrent with the Greenland Icecore Programme 1989-19 93 at Summit, 3200 m a.s.l. The sampling equipment is designed for col lection of weekly samples especially suited for PIXE analysis, retriev al once a year, automatic operation under extremely cold conditions an d very low energy consumption. Preliminary results from samples coveri ng for the first time also the winter season on the central Icecap are discussed in relation to arctic haze occurrences at sea level.