AN EULERIAN MODEL FOR ATMOSPHERIC TRANSPORT OF HEAVY-METALS OVER EUROPE - MODEL DESCRIPTION AND PRELIMINARY-RESULTS

This paper presents the Heavy Metals Eulerian Transport (HMET) model a nd simulation results for Europe for 1985. The HMET model takes into a ccount emission, atmospheric transport and deposition of As, Cd, Pb an d Zn computed on the EMEP grid system. Meteorological inputs consist o f the velocity field at 925 hPa, precipitation and mixing height. Velo city field and precipitation are updated every 6 hr during the model r un. New values of mixing height are available every 24 hr. The dry dep osition velocities for each metal are variable ia space and depend on the particle distribution function for.each particular metal. Wet depo sition is proportional to the precipitation intensity for the previous 6 hr and a constant scavenging ratio. Model equations are solved by m eans of the positive definite pseudospectral method which provides acc urate numerical solutions for the advection problem. Comparison of the model results with available observations for 1985 indicate a good ag reement for Cd and Pb, sufficient egreement for As and serious underes timation for Zn. Since the number of available observations for heavy metals in Europe in 1985 is relatively small, the model results presen ted in this paper should be considered as preliminary. However, the HM ET model performance in computing these results shows that it can be e asily and efficiently used as an operational tool and is especially us eful for estimating transboundary transport of heavy metals in Europe.