Vol. 118, No. 2 * Pages 93–191 * April – June 2014

N-deposition from atmosphere contributes to the eutrophication of Lake Balaton (Hungary). To estimate the share of N-input compared to the effect of other sources, measurements have started in the 70’s of the last century. However, in previous calculations the flux of N-gases (NH₃ and HNO₃) was estimated using deposition velocity parameters determined for terrestrial ecosystems. These simplifications were accompanied by an overestimation of the role of these compounds. According to our results for years 2001–2004, ammonia has a mean net emission flux from the lake (32.7 t N year^–1), while nitric acid deposition takes –21.8 t N year^–1 that are one order of magnitude lower than sum of other deposition forms (esp. wet N-deposition). The pH range in lake water (pH = 8.3–8.9) allows the bi-directional flux for ammonia. Ammonia exchange can act as a buffering system, i.e., in case of a high N-load to the lake from other sources (rivers, waste water, run-off, etc.) N-accumulations can be buffered through nitrogen emission in form of NH₃ as a consequence of the elevated compensation-point concentration. From this reason, eutrophication of Lake Balaton is phosphorus limited. Comparing the measured ammonia flux with the fluxes calculated by compensation-point models based on single Henry’s law theory and by Hales-Drewes theory, it can be concluded that in our case latter theory describes better the exchange processes, suggesting that effect of carbon dioxide on the solubility of ammonia can not be excluded. However, in contrast with Hales and Drewes who suggested a decreased solubility of ammonia in presence of CO₂, we find an opposite effect, i.e., CO₂ favors the solubility of ammonia in the slight alkaline pH-range representative to the lake.

Reliable long time series have key role in climatological research. Long term observations involve inhomogeneities due to change of measuring methods, sensors, surroundings of stations, or moving into a new location. Therefore, homogenization is necessary in order to make reliable analysis of datasets. In this study, the MASH (Multiple Analysis of Series for Homogenization) procedure developed at the Hungarian Meteorological Service was applied to improve our wind time series. Daily wind datasets were homogenized at 19 Hungarian synoptic stations in the period from 1975 to 2012. This paper discusses the validation of the homogenization process and presents the quality control results.

The aim of this study is to find the optimal spatialization method to model spatial differentiation of the climatic water balance (CWB). Monthly mean values from the period 1986–2010 for air temperature and precipitation as well as monthly solar radiation totals over Poland were considered in the study. Potential evapotranspiration data were calculated via the Turc formula.
Two simultaneous methods were used in the modeling: simple and multiple linear regression (with latitude, altitude, and distance from the coastline as variables) and the map algebra method. Map algebra was shown to be the better spatialization method; however, its optimization would require a reduction in the research scale and the use of more in-situ data. This would allow more local variables such as landform and land cover to be included in the analysis.

Climate is a decisive tourism resource and plays key role in the attractiveness of tourist destinations and the seasonality in tourism demand. The suitability of climate for general tourism purposes (i.e., sightseeing, shopping, and other light outdoor activities) is most frequently expressed by the Tourism Climatic Index (TCI), which combines several tourism-related climatic elements. In this study, the original TCI is modified in two ways. On the one hand, one of the most popular and widely used bioclimatic indices, Physiologically Equivalent Temperature (PET) is applied instead of effective temperature (ET) in the part of the index related to thermal comfort conditions. Furthermore, the TCI is adjusted to a ten-day scale since it is more relevant to tourism than the original monthly averages of the climatic parameters. Using the modified TCI we characterize and compare climatically suitable or even unfavorable places and periods of the year in case of some Hungarian and two other relatively close tourist destinations as examples. Analytical results indicate that the most optimal climatic conditions are in the shoulder seasons in all investigated places. The summer period is more unpleasant for sightseeing activities mainly due to the instense heat load. There are some remarkable differences between the cities in the time of occurence of different tourism climatic conditions and, therefore, in the seasonality conditions.

Acidification caused serious environmental problems over Europe in the 70’s and 80’s. The signs of the phenomenon were observed also in Hungary. However, a comprehensive assessment of acidic deposition on long term has not been carried out yet. Therefore, the purpose of this study is to assess the degree of this process and to investigate its long-term change in Hungary based on deposition time series for oxidized sulfur, oxidized nitrogen, and reduced nitrogen compounds. To achieve our goal, we used existing results of atmospheric chemistry transport models, and precipitation chemistry as well as background air pollution measurements at the Hungarian K-puszta site. Comparing the results with national emission datasets, we also made an attempt to interpret the changes in depositions. According to our time series (oxidized sulfur: 1880–2011, oxidized nitrogen: 1982–2012, reduced nitrogen: 1981–2012), the effect of acidification was most likely to intensify before 1980. Since then, the phenomenon presumably has been weakening gradually. In the case of oxidized sulfur and nitrogen compounds, transboundary transport has to be considered while comparing them to depositions. On the other hand, the impact of Hungarian industrial recession as well as the improvement of emission abatement techniques and national emission controlling measures can be observed not just on the emissions, but depositions as well. Moreover, we found that the atmospheric concentration and subsequent deposition of ammonia is strongly affected by the atmospheric concentration of sulfur dioxide, which highlights the need for further refinement of the estimation method for yearly dry deposition of ammonia.