2019. szeptember 22. vasárnap

Vol. 121, No. 1 * Pages 1–99 * January - March 2017

Quarterly journal og the Hungarian Meteological Service

Numerical simulation of sulfate formation in water drops: results of a box experiment
Gabriella Schmeller and István Geresdi
 PDF (3851 KB)   |   Abstract

The purpose of the research was to investigate how sulfate formation depends on the drop size, and to find efficient scheme for the numerical integration of ODEs (ordinary differential equations) describing absorption and chemical reactions. A box model was developed to simulate how the water drops absorb the different compounds and to simulate formation of sulfate by oxidation processes. Results show, that the length of time step necessary for the accurate integration of the differential equation depends on the drop size and on the concentration of the trace gases in the environment of the water drop. Analysis of the data suggests that the time step should be at least 0.01 s if the drop size is smaller than 20 µm, and it can be 0.1 s above this size. The time evolution of the pH of solution and that of the concentration of different compounds inside of water drops significantly depend on the size of the drops. In the case of water drops smaller than 50 µm, the concentration of the compounds becomes steady state in time interval less than 20 s, that is absorption and oxidation processes occur at almost same rate. In the case of larger drops, it takes significantly longer time to reach this balance. In the polluted atmosphere, the mass of the condensation nuclei can increase significantly due to the chemical processes occuring inside of the water drops. The results of this research will be used in a two-dimensional model simulating these processes in stratocumulus clouds with bin microphysical scheme.

Analyses of long-term and multi-site floral phenological observations of apple cultivars in comparison with temperature datasets
Panna Sepsi, Márta Ladányi, and Magdolna Tóth
 PDF (1427 KB)   |   Abstract

Three flowering stages were available for seven old apple cultivars in the database of Hungarian Meteorological Service. These old apple cultivars have more and more important role in the fruit production. The aim of this work is to describe the main flowering characteristics of these cultivars. Understanding the temporal nature and causes of phenological changes of such fruit trees is potentially valuable in the context of local climate change and associated yields, and more particularly for establishing appropriate horticultural management structures to ensure suitable future yields under changing orchard formation processes.

The effect of climate change on heat-related excess mortality in Hungary at different area levels
János Bobvos, Tibor Málnási, Tamás Rudnai, Dóra Cserbik, and Anna Páldy
 PDF (4683 KB)   |   Abstract

According to the 5th Assessment Report of IPCC, one of the greatest health impacts of climate change will be the heat-related excess mortality. In Hungary, the National Adaptation Geo-Information System (NAGiS) helps the adaptation process of climate change. Within CRIGiS project, which was initiated to extend the NAGiS, our special subtask was the assessment of heat-related excess mortality at different area levels in the present and for two predicted future periods. This assessment is described in this paper.
The Hungarian Central Statistical Office provided the daily mortality data for the period of May 1 – Sep 30, 2005–2014. The observed daily mean temperature data for the same period at small area level (NUTS 4, Nomenclature of territorial units for statistics) were provided by the Hungarian Meteorological Service (HMS). The modeled daily mean temperature data at NUTS 4 level based on the ALADIN-Climate model for three periods, May 1 – Sep 30 of 1991–2020, 2021–2050, and 2071–2100, were also provided by HMS.
The heatwave days were defined by the 90th percentile of the frequency distribution of daily mean temperatures at different area levels. The excess mortality was computed by extracting the mean daily mortality of cool days from the number of deaths on heatwave days. As we found a difference between the frequency distributions of observed and modeled present periods, a correction was done assuring that the yearly sums of excess mortality were the same in the observed and modeled present periods. Based on the corrected threshold values the changes in the future could be predicted.
During 2005–2014, the range of daily threshold temperature was between 22.3 °C and 25.4 °C, the mean excess mortality was 15.8% on the heatwave days at NUTS 4 level. At national level, daily mortality was higher by 51 cases on heatwave days than on cool days, which corresponded to an excess of 783 death cases per year in average. According to the climate model, the number and intensity of heatwave days will increase in relation to the present situation. Assuming the same population and level of sensitivity, for 2021–2050 a 2.6-fold, for 2071–2100 a 7.4-fold increase of excess deaths is predicted causing 2030 and 5800 cases per year, respectively.
The prediction of excess mortality at different area levels in the NAGiS database will help stakeholders to prepare adaptation measures to climate change.

Analysis of precipitation time series at Keszthely, Hungary (1871–2014)
Tímea Kocsis and Angéla Anda
 PDF (1294 KB)   |   Abstract

The results in the issue of local signs of global climate change at Keszthely (Hungary) are summarized and presented in this paper. The meteorological measurements at Keszthely have long history, a more than 140-year-long dataset of monthly amount of precipitation, provided by the University of Pannonia, is available for statistical analysis. The long-time series of precipitation amounts of Keszthely (Hungary) meteorological station was analyzed from the beginning of the observation (1871) until 2014, from the point of view of climate change. Simple climate-statistical analysis has been made in purpose to discover local climate alternations. Linear and exponential trends were fitted, and it was concluded that linear trends in every case had lower relative standard error than exponential trends, so linear changes were interpreted. Despite the fact that significant declining tendency was expected, the annual data does not show any modification in the tendency or variability, but other signs of the decreasing trend can be detected. Significant decreasing tendency was found in spring (–31.5 mm/100 years). Among the monthly sums, the precipitation amount of April (–14 mm/100 years) and October (–23.5 mm/100 years) showed statistically proved decreasing tendency. Variability is increasing significantly in September. These tendencies are unfavorable for the agricultural cultivation of the region.


Tourism climatic conditions of Hungary – present situation and assessment of future changes
Attila Kovács, Ákos Németh, János Unger, and Noémi Kántor
 PDF (6311 KB)   |   Abstract

This paper provides insight into the tourism-related outcomes of the Hungarian CRIGiS project, which was conducted in 2015. Based on tourism climatic indicators, this study aims at assessing the exposure of tourism sector to climate change. The widely known Tourism Climatic Index (TCI) is applied for the quantification of the climatic potential in Hungary in its original and modified form. This adjusted index version is suitable to reflect the seasonally different thermal perception patterns of Hungarian residents. These indicators were calculated based on past observations, and on the other hand, they rely on the outputs of regional climate model projections. The spatial distribution of the index values in Hungary is presented on a monthly basis and on district level, which is an administrative territorial unit in Hungary. The results indicate that, according to both versions of TCI, tourism climate conditions will likely to improve in the shoulder seasons and deteriorate in summer, remaining still at least acceptable for outdoor tourism purposes. The project outcomes are available for public use in the National Adaptation Geo-information System (NAGiS) developed in Hungary.