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Využití pozemní senzorové sítě pro kalibraci družicových dat dálkového průzkumu
Doubrava, Pavel ; Batrlová, Iva ; Kvapil, Jiří ; Seidlová, Jana
Dálkový průzkum Země je disciplína založená na fyzikálních principech. Naměřená data jsou zpracovávána matematicko-fyzikálními a matematickými metodami. Základním fyzikálním jevem, na kterém je dálkový průzkum založen, je interakce elektromagnetického záření se zkoumaným objektem. Informace o tom, jak probíhá tato interakce, nám udává energie, kterou zaznamenává detektor v přesně vymezených intervalech vlnových délek v daném prostorovém úhlu. Takto definovaná interakce je výchozí pro určování hledaných vlastností daných objektů. Každý objekt na zemském povrchu má vliv na naměřené hodnoty energie, a to jak v čase, tak v prostoru. Proto je nutné, aby tato energie byla měřena prostřednictvím kvantitativních fyzikálních veličin.
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Analýza energetické bilance intravilánu města pomocí metod dálkového průzkumu Země
ŠOUREK, David
The energy balance of each urban area depends on the specifics of active surface and other complex phenomena. In general, compared to the surrounding rural landscape, dry and impermeable surfaces predominate in urban areas. Different types of built-up areas have various properties determining how distributed solar radiation is. Overall, it is through energy fluxes defined by the sensible heat flux, the latent heat flux of evaporation, and the soil heat flux. Besides, vegetation plays a significant role in the proportions of fluxes. Plants can effectively transform the obtained solar radiation and thus influence the microclimatic situation through the cooling effect of evapotranspiration or other ecosystem services. Nevertheless, the efficiency depends on the state of vegetation and other prevailing conditions (weather, etc.). As the study area was selected the town of Písek. The research took place on two summer and two autumn days using remote sensing and statistical evaluation. The results showed the growing dependence of the latent heat flux of evaporation in localities with a higher vegetation density and a sufficient water supply. High values of surface temperature and sensible heat flux occurred in built-up areas with predominant materials with a large specific heat capacity, i.e. concrete, asphalt, sheet metal, stone etc. These indicators thus defined some problematic types of built-up areas, especially in terms of surface overheating or of the occurrence of local heat islands. Specifically, it was the historic centre, industrial zones and shopping centres. A better microclimatic situation prevailed in the park with a water surface, suburbs and built-up areas of family houses.
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Impact of different types of land cover on physical parameters of landscape surface
KUNTZMAN, Jan
The aim of the thesis was understanding the energy fluxes in different types of land cover. The area of interest is located in Novohradské hory in the basins of Váčkový and Pasecký potok. On a relatively small area there are five different types of land cover to be found (field, forest, permanent grassland, wetland and built-up area). For each of the types of land cover three properties of the surface were calculated: amount of vegetation on the surface, wetness of the surface and surface temperature. Moreover, soil heat flux, latent heat flux and sensible heat flux were established therefore surface thermal balance was evaluated. Results were statistically processed with boxplot diagrams as an outcome. The results support the hypothesis of vegetation having a positive effect on microclimate conditions. Especially the permanent cultures (wetlands, permanent grassland, forest) demonstrated much larger microclimatic stability and balance as well as capability of keeping moist. Thanks to insufficient intensity of vaporization (due to lack of water), built-up areas showed higher surface temperatures and sensible heat flux at most of the cases. Vegetation is capable of holding water and redistributing it in an environment via evapotranspiration. Thus, solar energy is stored inside of the water vapour which condensates on cool objects releasing the energy spent during the vaporization process. Water moves in the landscape through the local-scale water cycle stabilizing the microclimate.
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