Principal component analysis of data for trace elements and main components in precipitation falling on Norway.

Trace elements and the main components in precipitation were measured at three background sites in Norway. The work is based on weekly samples from 1989 and 1990. Principal component analysis was used to detect the covariation of the chemical components in the data set. Dominant factors are long-range atmospheric transport of anthropogenic components to Norway, crustal material, and marine sources. Different local sources also exist. The interpretation of seasonal variations in the data set is eased by studying the changes in the factor scores throughout the year. Distinct seasonal patterns are shown for some of the factors, in particular those representing soil dust and atmospheric transport from the marine environment.