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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]

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]