SIZE DISTRIBUTIONS OF ATMOSPHERIC TRACE-ELEMENTS AT DYE-3, GREENLAND .2. SOURCES AND TRANSPORT

Airborne concentrations and size distributions of 15 elements over the Greenland Ice Sheet have been measured during a one-month period in M arch 1989. The concentrations are relatively uniform, varying by less than a factor of three for virtually all of the elements. Notable exce ptions are Na and Cl which vary by more than an order of magnitude; th ese differences can probably be accounted for by the link with transpo rt from the oceans surrounding Greenland, although a significant fract ion of the Na is of crustal origin in some samples. The size distribut ions show strong peaks in the accumulation mode(0.4-1.0 mu m) or the c oarse particle mode (1.0-2.5 mu m); some species show bimodal distribu tions with the presence of both modes. The aerosol chemistry and size distribution data are consistent with back trajectories and local weat her conditions. For example, relatively high concentrations of Pb, Zn, Ni, Fe, and Mn in the accumulation mode during one of the runs are as sociated with trajectories from industrial regions of the Soviet Arcti c. The elements Si, Al, Fe, K, Ca, Mn, and Ti in the coarse mode are b elieved to be dominated by crustal sources. However, some runs show th e presence of an accumulation mode for most of these elements (with th e exception of Al), suggestive of combustion sources. Overall, the res ults show that use of an impactor with several submicron size cuts com bined with a suitable data inversion program can provide insights into the sources and transport of aerosols at remote locations such as the Greenland Ice Sheet.