Vol. 105, No. 3 * Pages 135–188 * July - September 2001

Reduction of sulfur emissions in Europe during the past decades have positively contributed to limit exposure to acidification. Based on long-range transport model computations by means of Danish Eulerian Model (DEM) as well as regional background concentration/deposition measurements, the transboundary contribution to the Hungarian sulfur concentration and deposition was estimated for the period of 1989–1998. It was found that despite the intense reduction of sulfur emission in Hungary during the period investigated, Hungary’s own sources still significantly contribute to the sulfur deposition in the country. Measured versus modeled sulfur data for Hungary as well as ratios of transboundary and Hungary’s own sulfur fluxes are presented and discussed in the paper.

Aerosol samples were collected using Berner-type cascade impactor and stacked filter units at Siófok during four campaigns in 1999 and 2000. A total of 40 bulk samples were measured using X-ray fluorescence (XRF). The concentrations of light elements in individual particles were calculated using a reverse Monte Carlo method developed at the University of Antwerp. The particles were further classified using hierarchical and non-hierarchical cluster analyses. Around 25,000 individual particles were analyzed by computer-controlled electron probe microanalysis (EPMA). In order to determine the possible sources of the aerosol particles, the combined data set of the bulk XRF and single-particle EPMA results was subjected to principal component analysis. The obtained analytical results were compared to the air mass backward trajectories, showing good correlation for the sampling periods. The composition of the aerosol did not show characteristic seasonal variation, it was more correlated to the origin of the incoming air mass.

A particular year is called extreme when the actual annual course of a climatic element differs substantially from the average annual course. This concept considers both the magnitude and length of departures from normal. A methodology to measure the difference between an actual and the average year is discussed. The procedure is applied to monthly mean temperatures and monthly precipitation amounts using ten locations in Hungary with homogeneous data sets from 1901 to 1999. Trends of above mentioned differences are analyzed. The chance for extreme years in overall decreases during last century, but there exists a slight tendency of more extreme years from the eighties. The most extreme temperature and precipitation years do not appear simultaneously.

The surface aerodynamic transfer parameterization method SAPA is presented. The method is based on the Monin-Obukhov similarity theory describing an implicit equation system of flux/profile relationships. The equation system is solved numerically using fixed-point method. This fixed-point method application is the unique and new feature of the scheme comparing to other schemes. We show that—though an iterative procedure is applied—the method seems to be reliable not only in the common but also in the extrem cases. This is demonstrated analysing the performance of the scheme in terms of both numerical and physical features. We tested also the goodness of the scheme on the Cabauw data set. The method considered can be applied in the land-surface parameterization schemes of weather and climate models.