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Insolation pattern and surface temperature on extrasolar planets
Káňová, Michaela ; Běhounková, Marie (advisor) ; Čadek, Ondřej (referee)
We study evolution and distribution of surface and near-surface temperature on tidally locked extrasolar terrestrial planets without atmosphere. In order to determine the temperature, insolation patterns depending on eccentricity, obliquity and spin-orbit resonance are computed and thermal diffusion equation is solved in a spherical shell. We discuss the dependence of temperature distribution on physical and geometrical parameters including orbit eccentricity, obliquity of rotational axis, type of spin-orbital resonance, thermal inertia and irradiance incident on the planetary surface (the extra- solar constant). The mean annual temperature is driven especially by the extrasolar constant and may rise up to thousand of kelvins in the most irradiated regions. Effect of eccentricity, obliquity and thermal inertia, in some cases, is on the scale of hundreds of kelvins.
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Evolution of terrestrial exoplanets
Káňová, Michaela ; Běhounková, Marie (advisor) ; Čadek, Ondřej (referee)
Observations of terrestrial exoplanets provide a unique statistical set that may improve our knowl- edge of their formation, structure as well as internal and orbital evolution. Close-in extrasolar planets are subjected to strong stellar tides, resulting in an extensive dissipation of mechanical energy (tidal heating), long-term orbital evolution and evolution of the rotational frequency. For the exoplanets on eccentric orbits, the traditional tidal theories predict locking into pseudo-synchronous spin states, for which the rotational frequency is slightly higher than the orbital frequency. Such predictions are, how- ever, in contradiction with the observations of moons in the Solar system, and are a consequence of simplified rheological assumptions. Here, we focus on a numerical approach to the tidal evolution of planetary orbit and rotation in a single-planet system, assuming a Maxwell viscoelastic rheology. We find equillibrium spin states, including the spin-orbit resonances, and discuss their connection with the minima of tidal heating. Locking into a spin-orbit resonance results in an irregular insolation pattern and an unequal surface temperature distribution, affecting the internal dynamics of the planet. The second part of the thesis therefore deals with the evaluation of the surface temperature and...
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Comparison of various approaches to evaluation of tree energetic balance
Tomková, Alžběta ; Pokorný, Jan (advisor) ; Lhotáková, Zuzana (referee)
The thesis deals with the tree energetic balance closely related to the phenomenon of plant transpiration. Living systems have a unique ability to equilibrate gradients in the nature. Storing energy of the incoming solar radiation into a latent heat of water evaporation is an example of such tree feature. It dissipates energy and simultaneously recycles nutrients and water in the ecosystem. There are few possible ways of energy balance detection shown in this work. The thermal imagining can be used as a method for an indirect indication of transpiration - transpiring plants have lower leaf surface temperature. An alternative method for determining the rate of transpiration is a direct measurement of transpiration on leaves or transpiration flow in a tree trunk. However, extrapolation of the above mentioned methods to entire stands can encounter some difficulties. The first part of the thesis presents a description of a physical background of energetic processes and the ways in which plants operate with water, the biotic pump theory is being discussed. The practical part begins with experiments on single leaves. These experiments are carried out to test the usability of the methods for the following experiments, which are performed on the entire living trees. They are focused on the relationship of the...
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Skin surface water temperatures determination in selected lakes and reservoirs from satellite data
Formánek, Tomáš ; Kolář, Jan (advisor) ; Brodský, Lukáš (referee)
LAKE SURFACE TEMPERATURE DETERMINED BY SATELLITE IMAGES Abstract The aim of this master thesis is to create a method to determine surface temperature of water in lake Osoyoos (LSWT - Lake Surface Water Temperature). It is necessary to know this temperature in order to make easier decisions in a paradigm of global warming processes. Thanks to LSWT it is possible to make a timeline visualisation of temperature development in years. The first chapter deals with a physical definition of how to get thermal information - the basis of remote thermal sensing is measuring of radiance intensity and it's transformation to brightness temperature. This radiation is not only influenced by atmospheric properties but also by local climatic and meteorological conditions, but it is also influenced by the relief. The thesis seeks to create a method for calculating surface temperature of lake Osoyoos located at Canadian-American border. This calculation is based on data provided by ASTER using a split-window method. The method works with the differences in bands of sensing in order to remove atmospheric influences. This thesis contains several charts, graphs and pictures. The final result of this paper is a map of distribution of lake surface water temperatures. Keywords: Thermal remote sensing, land surface temperature, ASTER, TIR
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Evolution of terrestrial exoplanets
Káňová, Michaela ; Běhounková, Marie (advisor) ; Čadek, Ondřej (referee)
Observations of terrestrial exoplanets provide a unique statistical set that may improve our knowl- edge of their formation, structure as well as internal and orbital evolution. Close-in extrasolar planets are subjected to strong stellar tides, resulting in an extensive dissipation of mechanical energy (tidal heating), long-term orbital evolution and evolution of the rotational frequency. For the exoplanets on eccentric orbits, the traditional tidal theories predict locking into pseudo-synchronous spin states, for which the rotational frequency is slightly higher than the orbital frequency. Such predictions are, how- ever, in contradiction with the observations of moons in the Solar system, and are a consequence of simplified rheological assumptions. Here, we focus on a numerical approach to the tidal evolution of planetary orbit and rotation in a single-planet system, assuming a Maxwell viscoelastic rheology. We find equillibrium spin states, including the spin-orbit resonances, and discuss their connection with the minima of tidal heating. Locking into a spin-orbit resonance results in an irregular insolation pattern and an unequal surface temperature distribution, affecting the internal dynamics of the planet. The second part of the thesis therefore deals with the evaluation of the surface temperature and...
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