A QUALITATIVE DETERMINATION OF THE SOURCE LOCATIONS OF PRECIPITATION CONSTITUENTS IN MORVAN, FRANCE

A statistical receptor-oriented model is developed to examine the long -range transport of precipitation constituents to the background stati on at Morvan (elevation 620 m, latitude 47 degrees 16' N and longitude 04 degrees 05' E), France. This model computes a probability function called PSCF (Potential Source Contribution Function) which is based o n the air parcel trajectory data coupled with precipitation chemical d ata associated to that air parcel. The PSCF value is the ratio of the probability of a contamined air parcel having traversed a 2 degrees la titude by 2 degrees longitude area to the probability that any air par cel traversed that area. Regions with high PSCF values thus have a hig her probability of contributing pollutants to the measured depositions at the receptor site. This approach suggests that the sources of the major acid forms (H2SO4 and HNO3) are located in the east of Germany a nd the middle of Great Britain, the Ca2+ sources in the Mediterranean basin and the Na+, Cl- and Mg2+ sources in the Atlantic Ocean.