2024. június 22. szombat
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Vol. 127, No. 4 * Pages 421–504 * October - December 2023

Journal of the Hungarrian Meteorological Service

Special issue: Application of advanced methods used for specific environmental purposes

Guest Editor: Kálmán Kovács

letöltés [pdf: 2891 KB]
Contribution of data-driven methods to risk reduction and climate change adaptation in Hungary and beyond
Edina Birinyi, Boglárka O. Lakatos, Márta Belényesi, Dániel Kristóf, Zsolt Hetesi, László Mrekva, and Gábor Mikus
DOI:10.28974/idojaras.2023.4.1 (pp. 421–446)
 PDF (7695 KB)   |   Abstract

Among a series of tangible phenomena related to climate change and ecosystem degradation, the severe drought damage that occurred in 2022 urges in particular a thoughtful and long-term concept to tackle and mitigate the effects of similar events. To develop this concept, in addition to taking stock of scientific results so far, it is crucial to establish the basis for mutually supportive cooperation between the sectors concerned, including agriculture, water management, and nature conservation.
As confirmed by scientific knowledge, the continuous deterioration of the landscape's water retention and evapotranspiration capacity is associated with weakening the climate regulating function and the degradation of agricultural production conditions. Accordingly, the task is not to find new resources and interventions ensuring the continuation of current landscape use; the real goal is to find the landscape use (farming methods and water use) that will ensure sustainable human livelihoods and environmental conditions.
All the tools and knowledge are available for the first steps and subsequent ongoing monitoring and refinement of a precautionary and prevention-based approach to support all levels of ecosystem services. With continuous professional dialogue and implementation of established and new methods, several goals can be achieved simultaneously, such as the integration of economic trends into the approach, the revitalization of Hungarian landscape culture, and hence the preservation of the rural workforce.

Evaluating dehazing techniques on artificial and satellite land surface images
András Fridvalszky, Balázs Tóth, and László Szécsi
DOI:10.28974/idojaras.2023.4.2 (pp. 447–457)
 PDF (1633 KB)   |   Abstract

Many image-based recognition tasks are highly susceptible to different types of natural phenomena like foggy weather, snow, or rain. The participating media will likely obscure important details necessary for these algorithms to work correctly. Still, these aspects could be recovered in certain situations with prior information about the underlying light interactions. This could be done with certain heuristics or with the nowadays popular deep-learning based methods. In this paper, we review and compare the results of two approaches to remove or scale down the effects of foggy weather. We also examine how these results can be applied to high resolution satellite images of land surfaces.

Forecasting critical weather front transitions based on locally measured meteorological data
Mátyás Szántó and László Vajta
DOI:10.28974/idojaras.2023.4.3 (pp. 459–471)
 PDF (834 KB)   |   Abstract

Certain types of medical meteorological phenomenontransitions can have a significant deteriorating effect on road safety conditions. Hence, a system that is capable of warning road users of the possibility of such conversions can prove to be utterly useful. Vehicles on different levels of automation (i.e., ones equipped with driver assistance systems – DAS) can use this information to adjust their parameters and become more cautious or warn the drivers to be more careful while driving. In this paper, we prove that identifying the critical type of weather front transition (i.e., no front to unstable cold front) is possible based on locally observable meteorological information. We present our method for classifying weather front transitions to non-critical versus critical types. Our developed machine learning model was trained on a dataset covering 10 years of meteorological data in Hungary, and it shows promising results with a recall value of 86%, and an F1-score of 60%.
As the developed method will form the basis of a patent, we are omitting key components and parameters of our solution from this paper.

A comparison of river streamflow measurement from optical and passive microwave radiometry
Zsófia Kugler and Viktor Győző Horváth
DOI:10.28974/idojaras.2023.4.4 (pp. 473–484)
 PDF (2389 KB)   |   Abstract

Climate change has a crucial impact on the global energy and water cycle. The hydrological cycle can be studied both from ground and satellite measurements on a global scale. Yet a comprehensive overview is challenging to establish given the spatial and temporal limitations related to various Earth Observation satellite sensors or maintenance of in-situ gauges. Optical remote sensing of visible light can not overcome the substantial obstacle from cloud cover that vastly limits its capability in daily global monitoring. Active satellite sensors like SAR or altimetry are not capable to provide global coverage on a daily basis, therefore, they can be geographically limited. Passive microwave radiometry (PMR) can acquire both daily and global scales that enables the temporally frequent and spatially extensive observations of continental river gauge. Previous studies demonstrated the use of PMR measurements for global daily river gauge benefiting from its high sensitivity of microwave radiation to water presence. This study aims at comparing the methodology of PMR to optical river gauge measurements based on the assumption that at selected locations along the river channel, increase in streamflow is related to increase in the floodplain water surface inundation. Comparison showed a significant obstacle of cloud cover over tropical regions, where PMR has the potential to measure river streamflow. Yet over regions with less clouds both optical and PMR can be good alternative to in-situ streamflow ground measurements. 

Climate change in the Debrecen area in the last 50 years and its impact on maize production
Béla Gombos, Zoltán Nagy, András Hajdu, and János Nagy
DOI:10.28974/idojaras.2023.4.5 (pp. 485–504)
 PDF (859 KB)   |   Abstract

The average yield of maize is significantly dependent on the meteorological conditions of the growing year. Both the most favorable weather conditions and the weather anomalies that tend to cause damage depend on the given phenophase. The aim of this research is to analyze the climatic changes that are important in maize production in the Hajdúság region.
For the climatological study of the area, homogenized temperature and precipitation data from the Hungarian Meteorological Service was used for the Debrecen region, which are freely available for download from the data repository of the institution. Trend analysis was performed for the last 50-year (1973–2022) and 30-year (1993–2022) periods. In total, 40 meteorological data series matching the study objective were analyzed. Linear regression calculations were performed using the SPSS 27 statistical software. For the non-parametric procedure, the MAKESENS Excel application was used, based on the Mann-Kendall (MK) test and Sen's slope estimation.
This research shows that the choice of the length of the study period affects the results of trend analysis. The numerical values of the trend slope for the 30-year vs. 50-year period differ, and for some parameters there are also substantial differences (e.g., trend sign). The results of the parametric and non-parametric trend analyses differed only marginally for the temperature variables included. Also, for precipitation data that do not follow a normal distribution (e.g., monthly), there were only a few significant differences. The trend in mean annual temperature shows an increase of 0.39 and 0.52 °C in 10 years, and an increase of around 2 °C in 50 years and 1.5 °C in 30 years. There is a significant warming in both the summer and winter half-years, with the summer half-year showing a steeper upward trend in the 50-year data series and the winter half-year in the 30-year data series. There is a clear pattern of large, highly significant warming in the summer months and less significant changes in the two spring and two autumn months that were observed. A negative, non-significant trend in annual precipitation is observed. The decreases of 17 mm and 24 mm/10 years obtained for the 50- and 30-year time series are not negligible from a practical point of view. For the summer half-year, the precipitation amount is decreasing, with a slope of -27 mm/10 years for the last 30 years, but even this value is not significant due to the high variability. There is no significant change in the amount of precipitation in the winter half-year over the last decades. Significant trends cannot be detected from monthly or even semi-annual or annual precipitation data. The Mann-Kendall test showed a trend decrease only in the 30-year April data series at the p=0.1 significance level. Overall, the changes are negative for maize production. It should be highlighted that the obvious warming, combined with a slight decrease in precipitation, is leading to a deterioration in crop water availability and a reduction in crop yields. The impact of the identified adverse climatic changes can be compensated to a significant extent by the proposed agrotechnical responses.

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