A Lagrangian Model of Long-Range Transport of Sulphur with the Diurnal Variations of Some Model Parameters

Abstract

A Lagrangian receptor-oriented one-layer model has been developed in order to simulate a synoptic-scale transport of airborne sulphur on a daily basis. Mass balance equations for sulphur dioxide and particulate sulphate were integrated along 3-day backward trajectories. Advective winds were determined from radiosonde reports, taking an average over the ground-based layer up to an 850-hPa level. The mixing height, transformation rate of sulphur dioxide to particulate sulphate, dry deposition velocities, and wet deposition rates for both pollutants were assumed to vary diurnally, depending on meteorological conditions. They were determined from routine synoptic observations. The model was tested for the sulphur dioxide and particulate sulphate data measured at nine and seven measuring sites, respectively. Daily mean calculated concentrations of both pollutants were generally higher than observed values for the test period. Both short- and long-term concentrations were predicted better for sulphur dioxide than for particulate sulphate. In application of the model to real data, problems arose due to incomplete input of meterological data (particularly in trajectory calculations).