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Response of tree rings and NDVI of Central-European conifers to extreme climatic events
Mašek, Jiří ; Treml, Václav (advisor) ; Šilhán, Karel (referee) ; Piermattei, Alma (referee)
Terrestrial ecosystems, mainly forests are important sinks of atmospheric carbon with high year-to-year variability driven by moisture availability. Trees store carbon in various compartments of the biomass, namely in stems, roots, and leaves. In this doctoral thesis, I investigated climate-growth responses of stem biomass (represented by tree rings) and leaf biomass (represented by normalized difference vegetation index; NDVI) of Pinus sylvestris and Picea abies in temperate forests of Czechia. I was interested in (i) general climate-growth responses and specifically, in reactions to drought and (ii) topographical factors influencing these responses at various spatial scales. We demonstrated that climate-growth responses of both species' tree rings in the lowlands revealed a significant positive and negative influence of moisture and temperature, respectively, while in higher elevations the responses were opposite. At a landscape level, the topography of relief modulated responses of Pinus sylvestris tree rings, while at the large-scale level, the geographical position and elevation (temperature gradients) were the main factors for both species. Responses of NDVI were slightly weaker compared to tree rings and did not show the influence of topography at any scale probably because vegetation...
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Analysis of Landscape Deforestation Using Satellite Imagery
Javorka, Martin ; Španěl, Michal (referee) ; Beran, Vítězslav (advisor)
Today is important to protect forest resources and tracking deforestation is essential. Re- mote sensing has an important role in this monitoring effort. This thesis studies four different techniques for detecting deforestation from satellite imagery - using both optical and radar data. The specifics of Earth observation data and geospatial analyses are described. The analytical techniques are used for detecting deforestation in the study area of Chocske vrchy. Image segmentation with Unet neural network model is used to classify there all deforested patches.
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Fusion of Radar and Visual Data for Remote Sensing
Strych, Tomáš ; Beran, Vítězslav (referee) ; Kolář, Martin (advisor)
Cieľom práce je vygenerovať satelitný optický snímok v prípade jeho nedostupnosti. Takýto snímok je vygenerovaný z aktuálneho radarového snímku a za pomoci radarových a optických snímkov z minulosti. Zameranie práce cieli na poľnohospodárstvo, kde sa na analýzu dát používajú rôzne vegetačné indexy. Pre zjednodušenie problematiky je práca zameraná len na optický snímok zobrazujúci NDVI. Boli vytvorené 4 dátové sady, pre prvé tri ročné obdobia a~štvrtý, ktorý ich spája. Pre riešenie problému preloženia obrázku z jedného na druhý bol použitý model Pix2Pix-cGAN. Výsledky práce zobrazujú rozdiely pri použití dátových sád, rozličného množstva a~typu použitých snímkov, tak ako aj intervalu medzi snímkami. Daným výskumom bolo zistené, že sieť je schopná vytvárať reálne uveriteľné obrázky s validnými numerickými hodnotami, avšak má problém správne využiť informáciu o radarovej zmene, ktorá je dôležitá pre ohodnotenie vývoja rastlín práve v prípade nedostupnosti optického snímku. Táto práca a~jej výsledky sú jedinečné vďaka naprieč Európou geograficky rozmanitej dátovej sade a vďaka zameraniu na agrikultúru, a to bez ohľadu na typ plodín.
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Prostorová analýza heterogenity pozemků z družicových dat
Kouřil, Jiří
Field heterogeneity is one of the prerequisites for many methods of precision agriculture, like for example variable sowing or variable application of fertilizers. One method of determining heterogeneity is an analysis of multispectral satellite images. The main aim of this thesis is to verify the hypothesis that there is at least a medium positive correlation between values of vegetation indices calculated from multispectral images and yields measured on four fields of a total area of approximately 75 ha during seasons 2019–2021. All fields are managed by the company Spearhead Czech s.r.o. which also provided data for preparing yield maps. These were statistically compared with three vegetation indices NDVI, EVI, and NDRE, which were calculated from Sentinel-2 satellite images. Results of correlation analysis show a medium correlation between vegetation indices and yields on two of four fields, whereas only weak positive and in some cases weak negative correlation can be observed on the other two. This was probably caused by droughts that influenced vegetation in these fields in 2019 and 2021. The thesis shows the potential of satellite images to determine field heterogeneity despite the comparison of vegetation indices and yields of different crops.
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Remote sensing as a forest management tool in Sub-Himalayan area in India
Kunwar, Haruhit
The Himalayan forests in India are home to very distinguished Himalayan flora and fauna, and the local population and livestock rely on forests because of the agrarian economy and pastoralism. The implementation of Remote Sensing and geotechnology tools in Forestry (precise forestry), has proved to support forest management. The sub-Himalayan area in India is one such region, that is largely forested and needs an application of Remote Sensing in Forest Management. This work has incorporated several geotechnology tools through which satellite imagery was processed and analyzed to have the outputs that will aid the foresters and forest managers with understanding the critical areas and implementing forest management plan with accuracy and precision, along with saving a lot of time.
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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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Nine-year bird community development on Radovesická spoil heap
KOREJS, Kryštof
Despite being valuable indicators of habitat change, birds are rarely used in restoration science. We surveyed birds on a large North-Bohemian spoil heap in 2012 and in 2019-21. We analysed bird community response to nine-year site development, human land use, primary vegetation productivity and proportion of senescent vegetation, vegetation age and structure, and restoration approach. Our findings offer an original insight into how birds respond to habitat characteristics, and highlight the importance of birds as indicators of restoration success.
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Testing possibilities to extract selected landscape characteristics for description of indication-relevant bird species habitats in the Krkonoše Mts. from remote sensing data
Polák, Mojmír ; Kupková, Lucie (advisor) ; Janík, Tomáš (referee)
The thesis uses remote sensing data from two spatial scales (Sentinel-2 with a 10 x 10 m pixel and PlanetScope 3 x 3 m. It explores the possibilities of extracting selected landscape characteristics (spectral indices, land cover type, landscape metrics). In order to evaluate which characteristics and at what scale are statistically significant for the occurrence of 23 selected bird species, species richness in quadrats and the number of species of the order Passeriformes in the Krkonoše Mountains. Data on species occurrence were mapped in the year 2012-2014 The strength of the relationship between characteristics and abundance was determined by Pearson's correlation coefficient. It could not be confirmed that data with higher spatial resolution would be more beneficial for extracting landscape characteristics. Overall, the landscape characteristics did not prove functional relationships for all selected species, but for some species, species richness, and order of Passeriformes, the assumption of elevation and land cover as important factors was confirmed. Land cover was analysed using the Random Forest supervised classification method in Google Earth Engine with an overall accuracy of 78 % for Sentinel-2 data, both in tundra and in the rest of the area, and 77 % for PlanetScoce data in tundra, 66...
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Fusion of Radar and Visual Data for Remote Sensing
Strych, Tomáš ; Beran, Vítězslav (referee) ; Kolář, Martin (advisor)
Cieľom práce je vygenerovať satelitný optický snímok v prípade jeho nedostupnosti. Takýto snímok je vygenerovaný z aktuálneho radarového snímku a za pomoci radarových a optických snímkov z minulosti. Zameranie práce cieli na poľnohospodárstvo, kde sa na analýzu dát používajú rôzne vegetačné indexy. Pre zjednodušenie problematiky je práca zameraná len na optický snímok zobrazujúci NDVI. Boli vytvorené 4 dátové sady, pre prvé tri ročné obdobia a~štvrtý, ktorý ich spája. Pre riešenie problému preloženia obrázku z jedného na druhý bol použitý model Pix2Pix-cGAN. Výsledky práce zobrazujú rozdiely pri použití dátových sád, rozličného množstva a~typu použitých snímkov, tak ako aj intervalu medzi snímkami. Daným výskumom bolo zistené, že sieť je schopná vytvárať reálne uveriteľné obrázky s validnými numerickými hodnotami, avšak má problém správne využiť informáciu o radarovej zmene, ktorá je dôležitá pre ohodnotenie vývoja rastlín práve v prípade nedostupnosti optického snímku. Táto práca a~jej výsledky sú jedinečné vďaka naprieč Európou geograficky rozmanitej dátovej sade a vďaka zameraniu na agrikultúru, a to bez ohľadu na typ plodín.
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Analysis of long-term changes of vegetation indices
Beránková, Petra ; Štych, Přemysl (advisor) ; Jedlička, Jan (referee)
The work deals with the issue of research of long-term changes of vegetation indices concretely indices NDVI (Normalized Difference Vegetation Index). The first part is devoted to detailed analysis of domestic and foreign literature, which deals with the calculation and interpretation of vegetation indices values. The main theme of this work is to explore relation between temperature and NDVI changes and precipitation and NDVI changes over the period 1982-2006. These connections are examined using correlation and regression analysis. Attention is concentrated to the Czech Republic, Central Europe and Finland. The average value of NDVI in Central Europe increased over the study period of 0,0012 per year. The average value of NDVI in Czech Republic increased of 0,0014 per year. On the territory of the Czech Republic increased the value of NDVI in three seasons (spring, autumn and winter). In the summer, in some areas, decreased NDVI values. Correlation coefficients between NDVI and temperature and NDVI and precipitation appeared consistently the highest in the spring. Keywords: NDVI, vegetation indices, temperature, precipitation, Central Europe, Czech Republic
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