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Tepelný ostrov města - analýza stavu a možnosti zlepšení
CHVOJKOVÁ, Aneta
Increasing surface temperature in urban environments along with the creation of heat islands is one of the most visible phenomena of a worsening climate in general. This phenomenon is inherently linked to the increasing rate of urbanisation and urban development. Heat islands in cities are formed by an accumulation of high surface temperatures and differ significantly from areas in their rural surroundings. The surface temperature depends on several factors. These include, including but not limited to, colour, permeability or material of the surface, as well as the presence of vegetation in the given area or the layout of the streets. Anthropogenic activity caused by fossil fuel combustion or transport also has a significant impact on the temperature in urban environments. One of the most efficient tools to reduce the rise in temperatures is in particular high-quality vegetation and water retention in urban environments and the landscape in general. The area of interest of this work, which deals with the topic described above, is Kardašova Řečice with twelve determined locations. Using satellite data analysis, problematic areas in terms of surface temperature and several smaller heat islands were identified. The results of the spectral vegetation indices analysis showed a mutual correlation between the surface temperature and the presence of vegetation, which was analysed by NDVI and NDMI spectral vegetation indices data. The highest temperatures and the lowest surface humidity were found in areas with the least vegetation (greenery). The situation was the opposite in areas with sufficient vegetation cover and water for evapotranspiration. Since vegetation has been proved to have a significant positive impact on reducing the surface temperature in urban environments, a strategy was suggested to improve the urban living conditions by implementing a suitably selected green and green-blue infrastructure.
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Statistical model of urban heat island characteristics in Central Europe
Vacík, Pavel ; Hošek, Jiří (advisor) ; Láska, Kamil (referee)
Urban heat island (UHI) is a region of increased air temperature in the canopy layer and boundary layer of the atmosphere above the town or industrial agglomeration in comparison with rural surroundings. The difference in temperature increases with the size of the city. This study describes the dependence of the intensity UHI Central European cities on their size and position of their weather station. It uses a multiple linear regression model. The dependent variable Y entering the model (data from 40 cities) are UHImean and UHImax. They are calculated as difference in air temperature between the urban and the relevant rural weather station. The average intensity of the urban heat island (UHImean) is the average value of the UHI of all available data in the analyzed period (hourly measurements of air temperature [řC] for the years 1994-2012). The data are only taken from night times records between 21:00 and 4:00 UTC and on days with the average total cloud cover at the city weather station less than 0,5. The maximum intensity of the urban heat island (UHImax) is the average maximum value of the UHI per night. The data are taken under the same conditions as in the case of UHImean. Independent variables X are the size of built-up area (X1) and the position of the weather station calculated using the...
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On the assessment of urbanization application in weather forecasting model
Nováková, Tereza ; Halenka, Tomáš (advisor) ; Žák, Michal (referee)
Built-up areas represent an artifiial impait to natural environment with large spatial variability and speiifi meihaniit radiationt thermal and ihemiial properties. Despite of inireasing horizontal resolution of numeriial weather prediition modelst the impait of loial built-up area on mesosynoptiv weather phenomena is still not well resolved. Therefore it is neiessary to use some of urban environment modelst whiih were designed to parameterize speiifi urban prosiessest not expliiitly resolved inside the grid box. In the thesis main urban iharaiteristiis are explained (impait on the struiture of boundary layert radiation and heat balanie of urban environment or urban heat island)t basii priniiples of urbanization appliiation in the numeriial weather model are desiribedt as well as different urban parameterizations available in numeriial model WRFe (Weather Reseaih and Feoreiasting). Number of validation experiments were performed for summer and winter episode in non-hydrostatii mode at 3t3 km resolutiont where different urban parametrizationst antropogenii heat adjustment and impait of mosaii land-use were tested. April 2018 Prague weather foreiast was verifiated in ionsideration of urban heat island.
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Statistical model of urban heat island characteristics in Central Europe
Vacík, Pavel ; Hošek, Jiří (advisor) ; Láska, Kamil (referee)
Urban heat island (UHI) is a region of increased air temperature in the canopy layer and boundary layer of the atmosphere above the town or industrial agglomeration in comparison with rural surroundings. The difference in temperature increases with the size of the city. This study describes the dependence of the intensity UHI Central European cities on their size and position of their weather station. It uses a multiple linear regression model. The dependent variable Y entering the model (data from 40 cities) are UHImean and UHImax. They are calculated as difference in air temperature between the urban and the relevant rural weather station. The average intensity of the urban heat island (UHImean) is the average value of the UHI of all available data in the analyzed period (hourly measurements of air temperature [řC] for the years 1994-2012). The data are only taken from night times records between 21:00 and 4:00 UTC and on days with the average total cloud cover at the city weather station less than 0,5. The maximum intensity of the urban heat island (UHImax) is the average maximum value of the UHI per night. The data are taken under the same conditions as in the case of UHImean. Independent variables X are the size of built-up area (X1) and the position of the weather station calculated using the...
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Evaluation of air temperature in relationship for urban heat island studies
Kalousová, Jitka ; Kožnarová, Věra (advisor) ; Lenka, Lenka (referee)
The present thesis deals with another current issue, which is known as the urban heat island. Phenomenon which aries by changes in the environment i divided into two categories namely natural and anthropogenic, this two categories can work together. City and counrtyside are different, the cause is the growing urbanization of towns and changing the earth´s surface, taht can absorb solar radiation and later released into the environment. The result of this process, the warming of the atmosphere in the cities.
In the literary part describes the historical development of climate, climate as a separate element and urban heat island. Urban heat island is also distributed through energy balance, causes, impacts and possible alternatives to eliminate ist mitigation.
The main objective was to describe the available evidence and evaluate data from four different European citites (Bourges, Hamburg, Karlov and Strasbourg). Furthermore to determine through maximum and minimum monthly temperatures in the summer months, whether in those cities discovers and develops this phenomenon. Further analyze the frequency of individual synoptic situations for the period 1961-2010 and evaluated their relationship to the air temperature.
In the first hypothesis was from statistical studies demonstrated, that in summer was markked ibcidence of urban heat island, which is especially noticeable in minimum temperatures. Further analysis demonstrated that the synoptic situation, when they have their effect on the urban heat island. The second hypothesis and it´s the air temperature changes are causes by human activities, and the result is creation of urban heat island to certify based on the evaluation of the data series.
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The importance of vegetation for climate forming in urban areas.
MARVALOVÁ, Jindra
Urban heat island is a phenomenon of different temperatures in cities compared to temperatures in the surrounding landscape. The intensity of this phenomenon can be influenced by the presence of vegetation in cities. There is evaluated the effect of vegetation on microclimate in various parts of the city České Budějovice in this thesis. The assessment is based on the evaluation of multispectral Landsat satellite images and thermal images, which were taken in-situ using thermal camera, and their statistical processing. The results show statistically significant differences in surface temperatures in the different areas of the city with a different amount of vegetation. Surface temperatures are significantly lower in areas with a large amount of vegetation than in areas without vegetation. Equally, selected vegetation surfaces have lower temperatures compared to anthropogenic surfaces, at least about 9 ° C.
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