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Recognizing the growing trend of the urban population and the undeniable fact of global and regional climate change, it becomes increasingly important to explore how we can improve the livability of our cities not only in the distant future but also in the next few years. A critical aspect of this endeavor involves studying how we can effectively mitigate human heat load in urban areas. In our research, in the case of a medium-sized city (Szeged, Hungary), we examined the effect of surface modifications caused by vegetation on human thermal perception during the day and night of two heatwave days. To achieve this, we used the MUKLIMO_3 micro-scale climate model to simulate the thermal climate of Szeged, while the thermal load was assessed with the perceived temperature calculated by the Klima-Michel model. Our analysis also relied on the local climate zone (LCZ) system to describe the original land cover and the additional urban green spaces in the study area. We scrutinized the effects of added vegetation of different types and densities, as well as the presence of protective forests surrounding the city. Our findings revealed that the effect of the added vegetation can only be detected on the modified surfaces and in their immediate vicinity. Notably, dense urban greenery resulted in up to a 2–3 °C reduction in perceived temperature in certain areas during the daytime, highlighting the profound impact of targeted green space development. In addition, it is crucial to consider the airflow-blocking effect of woody vegetation, which can increase thermal load by 1–3 °C in the areas located in a downwind direction. Therefore, the changing regional climatic conditions (e.g., wind direction) and the development of the right type and location of urban green areas deserve special attention during modern urban planning processes. [ABSTRACT FROM AUTHOR]

Since our climate is in a rapid changing phase, it is crucial to get information about the regional patterns of basic climatic parameters and indices. The EURO-CORDEX project provides high-quality regional climate model outputs, but these raw datasets are not convenient for the application in wider geoscience studies. According to the authors' knowledge, there is a lack of published spatial information about basic climate parameters and indices in Central Europe and especially in the broader Carpathian region therefore the basic aim of this study to fill this gap. The study presents the future trends in daily air temperature and precipitation and various climatic indices in the broader Carpathian Basin region during the 21st century. The indices are calculated using multi-model average temperature and precipitation data from EURO-CORDEX model simulations for the future time periods (2021-2050, 2071-2100) and emission scenarios (RCP4.5, RCP8.5). The indices present the future trends of the heat load, energy demand as well as extreme precipitation and drought characteristics. Based on the results the temperature increase is obvious and the heat load and energy demand quantifying indices follow the temperature trend. However, the trend is difficult to evaluate in the case of precipitation. The changes in the precipitation and the related indices can be considered small and appear within the regions. The future changes are the most considerable in the Carpathian Basin, but the entire examined region faces crucial changes in the following decades. [ABSTRACT FROM AUTHOR]

This study evaluates the pattern of a night-time climate index, namely the tropical nights (Tmin = 20 °C) during the 21st century in several different sized cities in the Carpathian Basin. For the modelling, MUKLIMO_3 microclimatic model and the cuboid statistical method were applied. In order to ensure the proper representation of the thermal characteristics of an urban landscape, the Local Climate Zone (LCZ) system was used as landuse information. For this work, LCZ maps were produced using WUDAPT methodology. The climatic input of the model was the Carpatclim dataset for the reference period (1981-2010) and EURO-CORDEX regional model outputs for the future time periods (2021-2050, 2071-2100) and emission scenarios (RCP4.5, RCP8.5). As results show, there would be a remarkable increase in the number of tropical nights along the century, and there is a clearly recognizable increase owing to urban landform. In the near past, the number of the index was 6-10 nights higher in the city core than the rural area where the number of this index was negligible. In the near future this urban-rural trend is the same, however, there is a slight increase (2-5 nights) in the index in city cores. At the end of the century, the results of the two emission scenarios become distinct. In the case of RCP4.5 the urban values are about 15-25 nights, what is less stressful compared to the 30-50 nights according to RCP8.5. The results clearly highlight that the effect of urban climate and climate change would cause serious risk for urban dwellers, therefore it is crucial to perform climate mitigation and adaptation actions on both global and urban scales. [ABSTRACT FROM AUTHOR]

ABSTRACT: The climate of the European region during 20th and 21st centuries in terms of Feddema's (2005) annual and seasonal climate characteristics is analysed. Observed data for the 20th century are taken from the CRU TS 1.2 data set. The projected data for the 21st century are obtained using simulation results of nine regional climate models run in the scope of the ENSEMBLES project. In the analysis, the European region is arbitrarily divided into three sub‐regions: the northern (72°–55°N), middle (55°–42°N) and southern (42°–35°N) zones. We focused on the analysis of the relationships between Feddema's climatic characteristics and the main geographical constraints (latitude, longitude, relief and land‐locked waterbodies). It is shown that Feddema's climatic maps agree well with the expected effects of the main geographical controls. Climate type/geographical control dependence is very strong in the upland coastal regions of the Atlantic Ocean, that is, in the Norwegian Alps, the Scottish Highlands and the Galician Massif Mountains. A characteristic seasonal‐type change can be observed in these regions: The seasonality of P changes through the seasonality of both P and T into the seasonality of T. This behaviour is registered by all model simulations in both the 20th and 21st centuries. The Atlantic Ocean–relief–longitude interplay effect on Feddema's climate types can be observed in all three zones. The uplands in Europe determine climate on the local scale. This upland effect is stronger when it is combined with the effect of extensive land‐locked water bodies. This relationship is obtained by all model simulations in both the 20th and 21st centuries. Lastly, the area heterogeneity of the European region's climate is well reproduced. The observations and the modelling tools show that the climate became and will become warmer and dryer during the course of the 20th and 21st centuries. [ABSTRACT FROM AUTHOR]

This study gives a comprehensive picture on the diurnal and seasonal general outdoor human thermal sensation levels in different urban quarters based on long-term (almost 3 years) data series from urban and rural areas of Szeged, Hungary. It is supplemented with a case study dealing with an extreme heat wave period which is more and more frequent in the last decades in the study area. The intra-urban comparison is based on a thermal aspect classification of the surface, namely, the local climate zone (LCZ) system, on an urban meteorological station network and on the utilization of the physiologically equivalent temperature (PET) comfort index with categories calibrated to the local population. The selected stations represent sunlit areas well inside the LCZ areas. The results show that the seasonal and annual average magnitudes of the thermal load exerted by LCZs in the afternoon and evening follow their LCZ numbers. It is perfectly in line with the LCZ concept originally concentrating only on air temperature ( T ) differences between the zones. Our results justified the subdivision of urban areas into LCZs and give significant support to the application possibilities of the LCZ concept as a broader term covering different thermal phenomena. [ABSTRACT FROM AUTHOR]

We analyse the average annual and seasonal air temperature conditions in the 'local climate zones' (LCZs) of Szeged, Hungary. The basis of our analysis is a 1-year dataset from 2014 to 2015 for a 20-station urban meteorological network. The network and its corresponding LCZ classes put temperature studies in Szeged into a new spatial framework to assess local climate and urban heat island (UHI) conditions. The stations were installed at locally representative sites using a Geographic Information System (GIS)method based on the standard surface parameters of the LCZ classification. The network was purposely designed to monitor thermal differences among LCZ classes in Szeged. We provide detailed site metadata for each of the monitoring stations used in the analysis. Our results show that the densely built-up LCZ classes have higher annual andmonthly mean and minimum air temperatures than structurally open and more vegetated classes, with nocturnal differences of >4 °C observed under calm, clear skies. Among select temperature indices measured in the urban LCZ classes, frost days, cooling degree-days, and tropical nights differ markedly from the background rural LCZ classes. This difference suggests that local climatologies exist within Szeged, and that these have implications for thermal comfort, urban energy use, and urban agriculture. Finally, the evaluation of heating and cooling rates in Szeged shows an important role for LCZs in UHI analysis. [ABSTRACT FROM AUTHOR]

In this paper the spatial pattern of Urban Heat Island (UHI) and its dynamical background are analysed. Furthermore, we examined the annual, seasonal and diurnal characteristics of UHI according to the Local Climate Zones (LCZs). The analysis was performed using one year (between June 2014 and May 2015) dataset from the measurement network of Szeged (Hungary). This network consists of 24 stations measuring air temperature and relative humidity. In the installation of the network the representativeness played an important role in order to that the stations represents their LCZs. We examined the thermal reactions during average and ideal conditions using the so-called weather factor. Our results show that the UHI is stronger in the compactly built zones and there are great differences between the zones. The greatest values appear in summer, while the difference is small in winter. The UHI starts to develop at sunset and exists through approximately 9-10 hours and differences are about 2 °C larger in case of ideal days, when the conditions (wind, cloud cover) are appropriate to the strong development of the UHI. The cooling rates show that the first few hours after sunset are determinative for the developing of UHI. In addition, the effect of UHI on annual mean temperature is also significant. [ABSTRACT FROM AUTHOR]

The present paper evaluates the alteration of certain night-time climate indices namely warm nights (Tmin > 17 °C) and tropical nights (Tmin ≥20 °C) during the 21st century in the city of Szeged. This examination was performed within the framework of a project founded by International Visegrad Fund, where the change of more climate indices were examined in several Central European cities. In this study the MUKLIMO_3 microclimatic model was used, which ensured the modelling of the local scale processes in the examined area. In the model for the land use we applied the Local Climate Zone (LCZ) system. In order to analyze longer periods the cuboid method was applied, which is a dynamical-statistical downscaling technique. We calculated the indices for 1981-2010 based on measurements and for 2021-2050 and 2071-2100 from the EURO-CORDEX datasets. In this study we present the results of Representative Concentration Pathways (RCP) scenarios namely RCP 4.5 and RCP 8.5. Our results show that highest values appear in the city centre and the number of the days clearly increases in the 21st century especially according to scenario RCP 8.5. The values depend on the built-up types and there are more days towards to the densely built-up LCZs. Moreover, considering the relative changes of the zones, larger values appear in sparsely built-up zones and natural surfaces. [ABSTRACT FROM AUTHOR]

• During a heat wave, LCZ 2 and 3 experience the highest heat load from 16.00 to 4.00. • Rural and urban areas in concave landforms and plains generate increased heat load (day). • Air temperature inversions decrease urban heat load in valley floors (night). Diurnal variability of spatial pattern of air temperature was studied in five cities in Central Europe: Bratislava (Slovakia), Brno (Czech Republic), Kraków (Poland), Szeged (Hungary) and Vienna (Austria), during one of the heat waves in 2015 (4–14 August), with the application of micro-climate model MUKLIMO_3. 8th August was chosen to study in detail the urban heat load at 10.00, 16.00, 22.00 and 4.00 CEST. Local Climate Zones concept was used to supply data for the model and for the interpretation of the results obtained. Model outcomes were validated with measurement data from 86 points belonging to the networks which operate in the cities studied. The results obtained show that among urban LCZ, the highest heat load was observed for LCZ 2 and 3 from 16.00 to 4.00, while at 10.00 there is no such clear pattern. Unlike forested areas, open green areas can contribute to the generation of high air temperature: >35°C during day time and >30°C during night time. Important factors controlling the intra-zonal and inter-zonal variability of air temperature in particular LCZs are the local environmental conditions. During the day time, diversified relief in the area of the city and its vicinities generates higher heat load in the valleys' floors than in areas located above, both in rural and urban areas. The same landforms experience lower heat load during the night time due to air temperature inversions effect. [ABSTRACT FROM AUTHOR]