2017. október 21. szombat
IDŐJÁRÁS - OMSZ angol nyelvű folyóirat

Vol. 121, No. 3 * Pages 209–328 * July - September 2017

Quarterly journal of the Hungarian Meteological Service

Satellite retrieval of severe storms based on the cloud microphysical profile over Central Europe
Michal Pokorny and Michal Zak
 PDF (6834 KB)   |   Abstract

The analysis of profiles of temperature (T) with regard to the effective radius (re) of cloud particles shows the vertical distribution of the effective particle size in clouds. The profiles are computed and constructed from satellite retrieved data and show graphically the distribution of the cloud particle size focused on convective clouds and convective storms subsequently. This special technique of severe storm analysis and forecasting, developed by Rosenfeld et al. (1998), has been tested in several countries around the world. Forecasting and predicting dangerous phenomena such as hailstorms or tornadoes that occur in severe storms is the main objective of this technique. This nowcasting tool is now also being tested in Central Europe for the first time. The basic description of the theory is presented in this paper including the results of our research, which confirms application of the theory in Central Europe in severe storm nowcasting. One typical severe and one nonsevere storm event in the Czech Republic and their vicinity are selected and described to show the main difference of T-re profiles in distinguishing of severe weather forecast. Furthermore, this paper discusses the possible benefits of this method for the Czech Weather Service, because it clearly reveals severe storm development in the monitored area.

The effect of climate and soil moisture on the tree-ring pattern of Turkey oak (Quercus cerris L.) in Central Transdanubia, Hungary
István Péter Kovács and Szabolcs Czigány
 PDF (2123 KB)   |   Abstract

Dendrochronological studies have revealed several environmental signals of many oak species supporting the suitability of these species for climate reconstruction (Haneca et al. 2009). Despite the large number of studies, limited information is available on the influence of climatic condition and soil moisture on the growth characteristics of Turkey oak (Q. cerris). Although soil moisture is probably the most limiting factor on growth of most oak species, relevant studies in Hungary primarily focused on the effect of temperature and rainfall, and ignored the impact of soil moisture. The combined analysis of climatic factors and soil moisture would reveal the importance of the influencing factors and would point out the anatomical patterns and environmental signals of a given area. In the current study, we analyzed the dendrochronological characteristics of a grove in Western Hungary (Central Transdanubian Region), and correlated tree anatomical patterns with the mean monthly temperatures, monthly precipitation totals, and modeled soil moisture at five different depths. The grove is exposed to environmental stress due to the local soil and climatic factors. Our findings indicate that the most pronounced environmental signal stored in the oaks is the change of soil moisture that exposes a direct impact on tree growth.

Leaf area index for common reed (Phragmites australis) with different water supplies in the Kis-Balaton wetland, Hungary, during two consecutive seasons (2014 and 2015)
Angéla Anda, Gábor Soós, and Jaime A. Teixeira da Silva
 PDF (877 KB)   |   Abstract

Seasonal progression of common reed (Phragmites australis) growth has been described by leaf area index (LAI), a key variable of crop growth, during two consecutive seasons at the Kis-Balaton wetland (KBW) in Hungary. The key objective of this study was to quantify the morphometric variability of LAI among common reed beds while distinguishing between established plant canopies with standing water (SR) and without water cover (DR). Seasonal mean LAI of plants with unlimited access to water was 3.21 ± 0.36 and 2.66 ± 0.34 for 2014 and 2015, respectively, while that of plants growing without water cover was 1.11 ± 0.22 and 0.89 ± 0.19. Common reed may be more sensitive to the presence or lack of continuous water cover than to variable weather conditions. Weekly LAI curves with two different water supplies as a function of growing degree day (GDD) were conducted to estimate the timing of peak LAI. Modeling the sums of seasonal evapotranspiration (ET) of swamp reed in SR showed only slight increases (56.3 mm and 50.8 mm) in 2014 and 2015, respectively. Total ET showed significant variation between both seasons, with the 2015 sum of ET being almost twice that of 2014. The findings of this study improve our knowledge about the growthofcommon reed LAI under variable weather conditions and water cover. The response of a plant, including LAI, to varying environments, may illuminate a course of action in wetland conservation programs. In addition, estimates of LAI based on meteorological variables might serve as useful inputs for different ET and growth models.

Analysis of the impacts of global warming on European bat species’s range area in the 21st century using regional climate model simulation
Júlia Anna Nagy, Judit Bartholy, Rita Pongrácz, Ildikó Pieczka, Hajnalka Breuer, and Levente Hufnagel
 PDF (3410 KB)   |   Abstract

Due to the projected climate change, the living territory of wild animals may be reshaped in the future, some of the species may even suffer extinction. The aim of this research is to make a comparative case study for the future predictions of the European terrestrial mammals' vulnerability to the climate change, by using their current range area maps (on the basis of The Atlas of the European Mammals). To characterize the climate indicators of the animals, we use the annual means and/or extremes of four climatic parameters (daily mean temperature, daily minimum temperature, daily maximum temperature, daily precipitation sum) based on the gridded E-OBS dataset for 1961–1990. Then, we determine specific percentiles of the climatic parameters for given species. The range area within the specific climatic intervals formed by the selected percentile pairs are mapped for the recent past (1961–1990), and also for the middle (2021–2050) and the end (2071–2100) of the 21st century using the RACMO (Regional Atmospheric Climate Model) simulation for the SRES A1B scenario. Our results suggest that, the optimal climatic requirements of the Pipistrellus pipistrellus may decrease and shift northward until the end of the 21st century. Moreover, this anaysis based on the climate indicator profile technique suggests a remarkable change in the habitats of all studied European bat species, and their northward migration in order to find their optimal conditions. As a result, from the recent past time period of 1961–1990, 63% of the studied European bat species will probably suffer habitat decrease, while 30% are likely to experience habitat increase, and 7% is projected to disappear by the end of the 21st century. Due to the projected regional climate change in Europe, habitat loss and degradation are the greatest threats to the studied bat species.

Meteorological conditions associated with West Nile fever incidences in Mediterranean and continental climates in Europe
Attila J. Trájer
 PDF (4011 KB)   |   Abstract

West Nile fever (WNF) is the most important mosquito-borne disease in several countries of Europe. The annual phenology of the infection is mainly influenced by the seasonal activity of mosquitoes and humans. Culicid mosquitoes, the main vectors of West Nile virus prefer humid and warm conditions. This study was aimed at analyzing the West Nile fever season in Greece, Hungary, Israel and the Palestinian territories, Italy, Romania, and Serbia comparing the effect of ambient temperatures and precipitation sums on the case number of the disease. The countries were divided into two main groups – Mediterranean and continental – based on their climate. Epidemiological data of the European Centre for Disease Prevention and Control and climatic data of the European Climate Assessment and Dataset were used in the analysis. In each of the studied countries, positive correlations (0.202 < r< 0.746; average: 0.531, SD: 0.23) were found between the monthly mean temperature and WNF case numbers. In contrast, in each of the studied countries negative correlations (–0.131 < r< –0.717; average: –0.360; SD: 0.25) were found between the monthly precipitation sums and WNF case numbers. The mean monthly temperature in months when WNF cases were observed ranged between 15.8–28.1 °C (SD: 4.73). The case number weighted mean of the monthly temperature during the WNF-affected months varied between 17.4 to 28.8 °C (SD: 4.40). West Nile fever seasons started in June or July at 18.9–24.0 °C mean monthly temperatures (average: 21.6 °C, SD: 1.65). The WNF season ended in October or November at 18.7–5.3 °C mean monthly temperature regimes (average: 10.1 °C, SD: 5.43). The maximum lengths of the seasons were 3 to 5 months. WNF cases mainly occur in the warm or hot summer continental, the hot and dry summer Mediterranean, and the subtropical areas of Europe. The found different strength of impacts of the precipitation sums on the WNF case numbers in the Mediterranean and temperate climate countries in summer can be explained by the fact that while in humid temperate regions mosquitoes can find their breeding habitats without extreme rainfall events, in the Mediterranean countries, heavy rainfalls create suitable breeding habitat waters for mosquitoes.

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